CVE-2025-21756

{"dataType": "CVE_RECORD", "dataVersion": "5.2", "cveMetadata": {"cveId": "CVE-2025-21756", "assignerOrgId": "416baaa9-dc9f-4396-8d5f-8c081fb06d67", "state": "PUBLISHED", "assignerShortName": "Linux", "dateReserved": "2024-12-29T08:45:45.760Z", "datePublished": "2025-02-27T02:18:11.547Z", "dateUpdated": "2026-10-15T01:04:00.229Z"}, "containers": {"cna": {"providerMetadata": {"orgId": "416baaa9-dc9f-4396-8d5f-8c081fb06d67", "shortName": "Linux", "dateUpdated": "2026-08-05T11:54:09.890Z"}, "descriptions": [{"lang": "en", "value": "In the Linux kernel, the following vulnerability has been resolved:\n\nvsock: Keep the binding until socket destruction\n\nPreserve sockets bindings; this includes both resulting from an explicit\nbind() and those implicitly bound through autobind during connect().\n\nPrevents socket unbinding during a transport reassignment, which fixes a\nuse-after-free:\n\n 1. vsock_create() (refcnt=1) calls vsock_insert_unbound() (refcnt=2)\n 2. transport->release() calls vsock_remove_bound() without checking if\n sk was bound and moved to bound list (refcnt=1)\n 3. vsock_bind() assumes sk is in unbound list and before\n __vsock_insert_bound(vsock_bound_sockets()) calls\n __vsock_remove_bound() which does:\n list_del_init(&vsk->bound_table); // nop\n sock_put(&vsk->sk); // refcnt=0\n\nBUG: KASAN: slab-use-after-free in __vsock_bind+0x62e/0x730\nRead of size 4 at addr ffff88816b46a74c by task a.out/2057\n dump_stack_lvl+0x68/0x90\n print_report+0x174/0x4f6\n kasan_report+0xb9/0x190\n __vsock_bind+0x62e/0x730\n vsock_bind+0x97/0xe0\n __sys_bind+0x154/0x1f0\n __x64_sys_bind+0x6e/0xb0\n do_syscall_64+0x93/0x1b0\n entry_SYSCALL_64_after_hwframe+0x76/0x7e\n\nAllocated by task 2057:\n kasan_save_stack+0x1e/0x40\n kasan_save_track+0x10/0x30\n __kasan_slab_alloc+0x85/0x90\n kmem_cache_alloc_noprof+0x131/0x450\n sk_prot_alloc+0x5b/0x220\n sk_alloc+0x2c/0x870\n __vsock_create.constprop.0+0x2e/0xb60\n vsock_create+0xe4/0x420\n __sock_create+0x241/0x650\n __sys_socket+0xf2/0x1a0\n __x64_sys_socket+0x6e/0xb0\n do_syscall_64+0x93/0x1b0\n entry_SYSCALL_64_after_hwframe+0x76/0x7e\n\nFreed by task 2057:\n kasan_save_stack+0x1e/0x40\n kasan_save_track+0x10/0x30\n kasan_save_free_info+0x37/0x60\n __kasan_slab_free+0x4b/0x70\n kmem_cache_free+0x1a1/0x590\n __sk_destruct+0x388/0x5a0\n __vsock_bind+0x5e1/0x730\n vsock_bind+0x97/0xe0\n __sys_bind+0x154/0x1f0\n __x64_sys_bind+0x6e/0xb0\n do_syscall_64+0x93/0x1b0\n entry_SYSCALL_64_after_hwframe+0x76/0x7e\n\nrefcount_t: addition on 0; use-after-free.\nWARNING: CPU: 7 PID: 2057 at lib/refcount.c:25 refcount_warn_saturate+0xce/0x150\nRIP: 0010:refcount_warn_saturate+0xce/0x150\n __vsock_bind+0x66d/0x730\n vsock_bind+0x97/0xe0\n __sys_bind+0x154/0x1f0\n __x64_sys_bind+0x6e/0xb0\n do_syscall_64+0x93/0x1b0\n entry_SYSCALL_64_after_hwframe+0x76/0x7e\n\nrefcount_t: underflow; use-after-free.\nWARNING: CPU: 7 PID: 2057 at lib/refcount.c:28 refcount_warn_saturate+0xee/0x150\nRIP: 0010:refcount_warn_saturate+0xee/0x150\n vsock_remove_bound+0x187/0x1e0\n __vsock_release+0x383/0x4a0\n vsock_release+0x90/0x120\n __sock_release+0xa3/0x250\n sock_close+0x14/0x20\n __fput+0x359/0xa80\n task_work_run+0x107/0x1d0\n do_exit+0x847/0x2560\n do_group_exit+0xb8/0x250\n __x64_sys_exit_group+0x3a/0x50\n x64_sys_call+0xfec/0x14f0\n do_syscall_64+0x93/0x1b0\n entry_SYSCALL_64_after_hwframe+0x76/0x7e"}], "metrics": [{"cvssV3_1": {"version": "3.1", "vectorString": "CVSS:3.1/AV:L/AC:L/PR:L/UI:N/S:U/C:H/I:H/A:H", "baseScore": 7.8, "baseSeverity": "HIGH"}, "scenarios": [{"lang": "en", "value": "Deterministic UAF in vsock socket binding during transport reassignment. connect() unbinds the socket dropping refcount, then bind() triggers use-after-free exploitable for privilege escalation."}]}], "affected": [{"product": "Linux", "vendor": "Linux", "defaultStatus": "unaffected", "repo": "https://git.kernel.org/pub/scm/linux/kernel/git/stable/linux.git", "programFiles": ["net/vmw_vsock/af_vsock.c"], "versions": [{"version": "c0cfa2d8a788fcf45df5bf4070ab2474c88d543a", "lessThan": "e7754d564579a5db9c5c9f74228df5d6dd6f1173", "status": "affected", "versionType": "git"}, {"version": "c0cfa2d8a788fcf45df5bf4070ab2474c88d543a", "lessThan": "e48fcb403c2d0e574c19683f09399ab4cf67809c", "status": "affected", "versionType": "git"}, {"version": "c0cfa2d8a788fcf45df5bf4070ab2474c88d543a", "lessThan": "42b33381e5e1f2b967dc4fb4221ddb9aaf10d197", "status": "affected", "versionType": "git"}, {"version": "c0cfa2d8a788fcf45df5bf4070ab2474c88d543a", "lessThan": "3f43540166128951cc1be7ab1ce6b7f05c670d8b", "status": "affected", "versionType": "git"}, {"version": "c0cfa2d8a788fcf45df5bf4070ab2474c88d543a", "lessThan": "645ce25aa0e67895b11d89f27bb86c9d444c40f8", "status": "affected", "versionType": "git"}, {"version": "c0cfa2d8a788fcf45df5bf4070ab2474c88d543a", "lessThan": "b1afd40321f1c243cffbcf40ea7ca41aca87fa5e", "status": "affected", "versionType": "git"}, {"version": "c0cfa2d8a788fcf45df5bf4070ab2474c88d543a", "lessThan": "fcdd2242c0231032fc84e1404315c245ae56322a", "status": "affected", "versionType": "git"}]}, {"product": "Linux", "vendor": "Linux", "defaultStatus": "affected", "repo": "https://git.kernel.org/pub/scm/linux/kernel/git/stable/linux.git", "programFiles": ["net/vmw_vsock/af_vsock.c"], "versions": [{"version": "5.5", "status": "affected"}, {"version": "0", "lessThan": "5.5", "status": "unaffected", "versionType": "semver"}, {"version": "5.10.235", "lessThanOrEqual": "5.10.*", "status": "unaffected", "versionType": "semver"}, {"version": "5.15.179", "lessThanOrEqual": "5.15.*", "status": "unaffected", "versionType": "semver"}, {"version": "6.1.131", "lessThanOrEqual": "6.1.*", "status": "unaffected", "versionType": "semver"}, {"version": "6.6.79", "lessThanOrEqual": "6.6.*", "status": "unaffected", "versionType": "semver"}, {"version": "6.12.16", "lessThanOrEqual": "6.12.*", "status": "unaffected", "versionType": "semver"}, {"version": "6.13.4", "lessThanOrEqual": "6.13.*", "status": "unaffected", "versionType": "semver"}, {"version": "6.14", "lessThanOrEqual": "*", "status": "unaffected", "versionType": "original_commit_for_fix"}]}], "cpeApplicability": [{"nodes": [{"operator": "OR", "negate": false, "cpeMatch": [{"vulnerable": true, "criteria": "cpe:2.3:o:linux:linux_kernel:*:*:*:*:*:*:*:*", "versionStartIncluding": "5.5", "versionEndExcluding": "5.10.235"}, {"vulnerable": true, "criteria": "cpe:2.3:o:linux:linux_kernel:*:*:*:*:*:*:*:*", "versionStartIncluding": "5.5", "versionEndExcluding": "5.15.179"}, {"vulnerable": true, "criteria": "cpe:2.3:o:linux:linux_kernel:*:*:*:*:*:*:*:*", "versionStartIncluding": "5.5", "versionEndExcluding": "6.1.131"}, {"vulnerable": true, "criteria": "cpe:2.3:o:linux:linux_kernel:*:*:*:*:*:*:*:*", "versionStartIncluding": "5.5", "versionEndExcluding": "6.6.79"}, {"vulnerable": true, "criteria": "cpe:2.3:o:linux:linux_kernel:*:*:*:*:*:*:*:*", "versionStartIncluding": "5.5", "versionEndExcluding": "6.12.16"}, {"vulnerable": true, "criteria": "cpe:2.3:o:linux:linux_kernel:*:*:*:*:*:*:*:*", "versionStartIncluding": "5.5", "versionEndExcluding": "6.13.4"}, {"vulnerable": true, "criteria": "cpe:2.3:o:linux:linux_kernel:*:*:*:*:*:*:*:*", "versionStartIncluding": "5.5", "versionEndExcluding": "6.14"}]}]}], "references": [{"url": "https://git.kernel.org/stable/c/e7754d564579a5db9c5c9f74228df5d6dd6f1173"}, {"url": "https://git.kernel.org/stable/c/e48fcb403c2d0e574c19683f09399ab4cf67809c"}, {"url": "https://git.kernel.org/stable/c/42b33381e5e1f2b967dc4fb4221ddb9aaf10d197"}, {"url": "https://git.kernel.org/stable/c/3f43540166128951cc1be7ab1ce6b7f05c670d8b"}, {"url": "https://git.kernel.org/stable/c/645ce25aa0e67895b11d89f27bb86c9d444c40f8"}, {"url": "https://git.kernel.org/stable/c/b1afd40321f1c243cffbcf40ea7ca41aca87fa5e"}, {"url": "https://git.kernel.org/stable/c/fcdd2242c0231032fc84e1404315c245ae56322a"}], "title": "vsock: Keep the binding until socket destruction", "x_generator": {"engine": "bippy-1.2.0"}}, "adp": [{"problemTypes": [{"descriptions": [{"type": "CWE", "cweId": "CWE-416", "lang": "en", "description": "CWE-416 Use After Free"}]}], "metrics": [{"cvssV3_1": {"scope": "UNCHANGED", "version": "3.1", "baseScore": 7.8, "attackVector": "LOCAL", "baseSeverity": "HIGH", "vectorString": "CVSS:3.1/AV:L/AC:L/PR:L/UI:N/S:U/C:H/I:H/A:H", "integrityImpact": "HIGH", "userInteraction": "NONE", "attackComplexity": "LOW", "availabilityImpact": "HIGH", "privilegesRequired": "LOW", "confidentialityImpact": "HIGH"}}, {"other": {"type": "ssvc", "content": {"timestamp": "2025-08-14T21:01:56.187542Z", "id": "CVE-2025-21756", "options": [{"Exploitation": "poc"}, {"Automatable": "no"}, {"Technical Impact": "total"}], "role": "CISA Coordinator", "version": "2.0.3"}}}], "title": "CISA ADP Vulnrichment", "providerMetadata": {"orgId": "134c704f-9b21-4f2e-91b3-4a467353bcc0", "shortName": "CISA-ADP", "dateUpdated": "2025-08-14T21:02:02.327Z"}}, {"title": "CVE Program Container", "references": [{"url": "https://lists.debian.org/debian-lts-announce/2025/05/msg00045.html"}, {"url": "https://lists.debian.org/debian-lts-announce/2025/05/msg00030.html"}], "providerMetadata": {"orgId": "af854a3a-2127-422b-91ae-364da2661108", "shortName": "CVE", "dateUpdated": "2025-11-03T19:37:01.186Z"}}, {"x_adpType": "supplier", "providerMetadata": {"orgId": "0b142b55-0307-4c5a-b3c9-f314f3fb7c5e", "shortName": "siemens-SADP", "dateUpdated": "2026-10-15T01:04:00.229Z"}, "affected": [{"vendor": "Siemens", "product": "SIMATIC S7-1500 CPU 1518-4 PN/DP MFP", "versions": [{"status": "affected", "version": "V3.1.5", "lessThan": "*", "versionType": "custom"}], "defaultStatus": "unknown"}, {"vendor": "Siemens", "product": "SIMATIC S7-1500 CPU 1518-4 PN/DP MFP", "versions": [{"status": "affected", "version": "V3.1.5", "lessThan": "*", "versionType": "custom"}], "defaultStatus": "unknown"}, {"vendor": "Siemens", "product": "SIMATIC S7-1500 CPU 1518F-4 PN/DP MFP", "versions": [{"status": "affected", "version": "V3.1.5", "lessThan": "*", "versionType": "custom"}], "defaultStatus": "unknown"}, {"vendor": "Siemens", "product": "SIMATIC S7-1500 CPU 1518F-4 PN/DP MFP", "versions": [{"status": "affected", "version": "V3.1.5", "lessThan": "*", "versionType": "custom"}], "defaultStatus": "unknown"}, {"vendor": "Siemens", "product": "SIMATIC S7-1500 TM MFP - GNU/Linux subsystem", "versions": [{"status": "affected", "version": "0", "lessThan": "*", "versionType": "custom"}], "defaultStatus": "unknown"}, {"vendor": "Siemens", "product": "SIMATIC S7-1500 TM MFP - GNU/Linux subsystem", "versions": [{"status": "affected", "version": "0", "lessThan": "*", "versionType": "custom"}], "defaultStatus": "unknown"}, {"vendor": "Siemens", "product": "SIPLUS S7-1500 CPU 1518-4 PN/DP MFP", "versions": [{"status": "affected", "version": "V3.1.5", "lessThan": "*", "versionType": "custom"}], "defaultStatus": "unknown"}], "references": [{"url": "https://cert-portal.siemens.com/productcert/html/ssa-265688.html"}, {"url": "https://cert-portal.siemens.com/productcert/html/ssa-082556.html"}, {"url": "https://cert-portal.siemens.com/productcert/html/ssa-784472.html"}]}]}}

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"type": "CWE", "cweId": "CWE-416", "description": "CWE-416 Use After Free"}]}], "providerMetadata": {"orgId": "134c704f-9b21-4f2e-91b3-4a467353bcc0", "shortName": "CISA-ADP", "dateUpdated": "2025-02-27T18:14:20.000Z"}}], "cna": {"title": "vsock: Keep the binding until socket destruction", "metrics": [{"cvssV3_1": {"version": "3.1", "baseScore": 7.8, "baseSeverity": "HIGH", "vectorString": "CVSS:3.1/AV:L/AC:L/PR:L/UI:N/S:U/C:H/I:H/A:H"}, "scenarios": [{"lang": "en", "value": "Deterministic UAF in vsock socket binding during transport reassignment. connect() unbinds the socket dropping refcount, then bind() triggers use-after-free exploitable for privilege escalation."}]}], "affected": [{"repo": "https://git.kernel.org/pub/scm/linux/kernel/git/stable/linux.git", "vendor": "Linux", "product": "Linux", "versions": [{"status": "affected", "version": "c0cfa2d8a788fcf45df5bf4070ab2474c88d543a", "lessThan": "e7754d564579a5db9c5c9f74228df5d6dd6f1173", "versionType": "git"}, {"status": "affected", "version": "c0cfa2d8a788fcf45df5bf4070ab2474c88d543a", "lessThan": "e48fcb403c2d0e574c19683f09399ab4cf67809c", "versionType": "git"}, {"status": "affected", "version": "c0cfa2d8a788fcf45df5bf4070ab2474c88d543a", "lessThan": "42b33381e5e1f2b967dc4fb4221ddb9aaf10d197", "versionType": "git"}, {"status": "affected", "version": "c0cfa2d8a788fcf45df5bf4070ab2474c88d543a", "lessThan": "3f43540166128951cc1be7ab1ce6b7f05c670d8b", "versionType": "git"}, {"status": "affected", "version": "c0cfa2d8a788fcf45df5bf4070ab2474c88d543a", "lessThan": "645ce25aa0e67895b11d89f27bb86c9d444c40f8", "versionType": "git"}, {"status": "affected", "version": "c0cfa2d8a788fcf45df5bf4070ab2474c88d543a", "lessThan": "b1afd40321f1c243cffbcf40ea7ca41aca87fa5e", "versionType": "git"}, {"status": "affected", "version": "c0cfa2d8a788fcf45df5bf4070ab2474c88d543a", "lessThan": "fcdd2242c0231032fc84e1404315c245ae56322a", "versionType": "git"}], "programFiles": ["net/vmw_vsock/af_vsock.c"], "defaultStatus": "unaffected"}, {"repo": "https://git.kernel.org/pub/scm/linux/kernel/git/stable/linux.git", "vendor": "Linux", "product": "Linux", "versions": [{"status": "affected", "version": "5.5"}, {"status": "unaffected", "version": "0", "lessThan": "5.5", "versionType": "semver"}, {"status": "unaffected", "version": "5.10.235", "versionType": "semver", "lessThanOrEqual": "5.10.*"}, {"status": "unaffected", "version": "5.15.179", "versionType": "semver", "lessThanOrEqual": "5.15.*"}, {"status": "unaffected", "version": "6.1.131", "versionType": "semver", "lessThanOrEqual": "6.1.*"}, {"status": "unaffected", "version": "6.6.79", "versionType": "semver", "lessThanOrEqual": "6.6.*"}, {"status": "unaffected", "version": "6.12.16", "versionType": "semver", "lessThanOrEqual": "6.12.*"}, {"status": "unaffected", "version": "6.13.4", "versionType": "semver", "lessThanOrEqual": "6.13.*"}, {"status": "unaffected", "version": "6.14", "versionType": "original_commit_for_fix", "lessThanOrEqual": "*"}], "programFiles": ["net/vmw_vsock/af_vsock.c"], "defaultStatus": "affected"}], "references": [{"url": "https://git.kernel.org/stable/c/e7754d564579a5db9c5c9f74228df5d6dd6f1173"}, {"url": "https://git.kernel.org/stable/c/e48fcb403c2d0e574c19683f09399ab4cf67809c"}, {"url": "https://git.kernel.org/stable/c/42b33381e5e1f2b967dc4fb4221ddb9aaf10d197"}, {"url": "https://git.kernel.org/stable/c/3f43540166128951cc1be7ab1ce6b7f05c670d8b"}, {"url": "https://git.kernel.org/stable/c/645ce25aa0e67895b11d89f27bb86c9d444c40f8"}, {"url": "https://git.kernel.org/stable/c/b1afd40321f1c243cffbcf40ea7ca41aca87fa5e"}, {"url": "https://git.kernel.org/stable/c/fcdd2242c0231032fc84e1404315c245ae56322a"}], "x_generator": {"engine": "bippy-1.2.0"}, "descriptions": [{"lang": "en", "value": "In the Linux kernel, the following vulnerability has been resolved:\n\nvsock: Keep the binding until socket destruction\n\nPreserve sockets bindings; this includes both resulting from an explicit\nbind() and those implicitly bound through autobind during connect().\n\nPrevents socket unbinding during a transport reassignment, which fixes a\nuse-after-free:\n\n 1. vsock_create() (refcnt=1) calls vsock_insert_unbound() (refcnt=2)\n 2. transport->release() calls vsock_remove_bound() without checking if\n sk was bound and moved to bound list (refcnt=1)\n 3. vsock_bind() assumes sk is in unbound list and before\n __vsock_insert_bound(vsock_bound_sockets()) calls\n __vsock_remove_bound() which does:\n list_del_init(&vsk->bound_table); // nop\n sock_put(&vsk->sk); // refcnt=0\n\nBUG: KASAN: slab-use-after-free in __vsock_bind+0x62e/0x730\nRead of size 4 at addr ffff88816b46a74c by task a.out/2057\n dump_stack_lvl+0x68/0x90\n print_report+0x174/0x4f6\n kasan_report+0xb9/0x190\n __vsock_bind+0x62e/0x730\n vsock_bind+0x97/0xe0\n __sys_bind+0x154/0x1f0\n __x64_sys_bind+0x6e/0xb0\n do_syscall_64+0x93/0x1b0\n entry_SYSCALL_64_after_hwframe+0x76/0x7e\n\nAllocated by task 2057:\n kasan_save_stack+0x1e/0x40\n kasan_save_track+0x10/0x30\n __kasan_slab_alloc+0x85/0x90\n kmem_cache_alloc_noprof+0x131/0x450\n sk_prot_alloc+0x5b/0x220\n sk_alloc+0x2c/0x870\n __vsock_create.constprop.0+0x2e/0xb60\n vsock_create+0xe4/0x420\n __sock_create+0x241/0x650\n __sys_socket+0xf2/0x1a0\n __x64_sys_socket+0x6e/0xb0\n do_syscall_64+0x93/0x1b0\n entry_SYSCALL_64_after_hwframe+0x76/0x7e\n\nFreed by task 2057:\n kasan_save_stack+0x1e/0x40\n kasan_save_track+0x10/0x30\n kasan_save_free_info+0x37/0x60\n __kasan_slab_free+0x4b/0x70\n kmem_cache_free+0x1a1/0x590\n __sk_destruct+0x388/0x5a0\n __vsock_bind+0x5e1/0x730\n vsock_bind+0x97/0xe0\n __sys_bind+0x154/0x1f0\n __x64_sys_bind+0x6e/0xb0\n do_syscall_64+0x93/0x1b0\n entry_SYSCALL_64_after_hwframe+0x76/0x7e\n\nrefcount_t: addition on 0; use-after-free.\nWARNING: CPU: 7 PID: 2057 at lib/refcount.c:25 refcount_warn_saturate+0xce/0x150\nRIP: 0010:refcount_warn_saturate+0xce/0x150\n __vsock_bind+0x66d/0x730\n vsock_bind+0x97/0xe0\n __sys_bind+0x154/0x1f0\n __x64_sys_bind+0x6e/0xb0\n do_syscall_64+0x93/0x1b0\n entry_SYSCALL_64_after_hwframe+0x76/0x7e\n\nrefcount_t: underflow; use-after-free.\nWARNING: CPU: 7 PID: 2057 at lib/refcount.c:28 refcount_warn_saturate+0xee/0x150\nRIP: 0010:refcount_warn_saturate+0xee/0x150\n vsock_remove_bound+0x187/0x1e0\n __vsock_release+0x383/0x4a0\n vsock_release+0x90/0x120\n __sock_release+0xa3/0x250\n sock_close+0x14/0x20\n __fput+0x359/0xa80\n task_work_run+0x107/0x1d0\n do_exit+0x847/0x2560\n do_group_exit+0xb8/0x250\n __x64_sys_exit_group+0x3a/0x50\n x64_sys_call+0xfec/0x14f0\n do_syscall_64+0x93/0x1b0\n entry_SYSCALL_64_after_hwframe+0x76/0x7e"}], "cpeApplicability": [{"nodes": [{"negate": false, "cpeMatch": [{"criteria": "cpe:2.3:o:linux:linux_kernel:*:*:*:*:*:*:*:*", "vulnerable": true, "versionEndExcluding": "5.10.235", "versionStartIncluding": "5.5"}, {"criteria": "cpe:2.3:o:linux:linux_kernel:*:*:*:*:*:*:*:*", "vulnerable": true, "versionEndExcluding": "5.15.179", "versionStartIncluding": "5.5"}, {"criteria": "cpe:2.3:o:linux:linux_kernel:*:*:*:*:*:*:*:*", "vulnerable": true, "versionEndExcluding": "6.1.131", "versionStartIncluding": "5.5"}, {"criteria": "cpe:2.3:o:linux:linux_kernel:*:*:*:*:*:*:*:*", "vulnerable": true, "versionEndExcluding": "6.6.79", "versionStartIncluding": "5.5"}, {"criteria": "cpe:2.3:o:linux:linux_kernel:*:*:*:*:*:*:*:*", "vulnerable": true, "versionEndExcluding": "6.12.16", "versionStartIncluding": "5.5"}, {"criteria": "cpe:2.3:o:linux:linux_kernel:*:*:*:*:*:*:*:*", "vulnerable": true, "versionEndExcluding": "6.13.4", "versionStartIncluding": "5.5"}, {"criteria": "cpe:2.3:o:linux:linux_kernel:*:*:*:*:*:*:*:*", "vulnerable": true, "versionEndExcluding": "6.14", "versionStartIncluding": "5.5"}], "operator": "OR"}]}], "providerMetadata": {"orgId": "416baaa9-dc9f-4396-8d5f-8c081fb06d67", "shortName": "Linux", "dateUpdated": "2026-08-05T11:54:09.890Z"}}}, "cveMetadata": {"cveId": "CVE-2025-21756", "state": "PUBLISHED", "dateUpdated": "2026-10-15T01:04:00.229Z", "dateReserved": "2024-12-29T08:45:45.760Z", "assignerOrgId": "416baaa9-dc9f-4396-8d5f-8c081fb06d67", "datePublished": "2025-02-27T02:18:11.547Z", "assignerShortName": "Linux"}, "dataVersion": "5.2"}

{"affected": [{"affectedData": [{"defaultStatus": "unaffected", "product": "Linux", "programFiles": ["net/vmw_vsock/af_vsock.c"], "repo": "https://git.kernel.org/pub/scm/linux/kernel/git/stable/linux.git", "vendor": "Linux", "versions": [{"lessThan": "e7754d564579a5db9c5c9f74228df5d6dd6f1173", "status": "affected", "version": "c0cfa2d8a788fcf45df5bf4070ab2474c88d543a", "versionType": "git"}, {"lessThan": "e48fcb403c2d0e574c19683f09399ab4cf67809c", "status": "affected", "version": "c0cfa2d8a788fcf45df5bf4070ab2474c88d543a", "versionType": "git"}, {"lessThan": "42b33381e5e1f2b967dc4fb4221ddb9aaf10d197", "status": "affected", "version": "c0cfa2d8a788fcf45df5bf4070ab2474c88d543a", "versionType": "git"}, {"lessThan": "3f43540166128951cc1be7ab1ce6b7f05c670d8b", "status": "affected", "version": "c0cfa2d8a788fcf45df5bf4070ab2474c88d543a", "versionType": "git"}, {"lessThan": "645ce25aa0e67895b11d89f27bb86c9d444c40f8", "status": "affected", "version": "c0cfa2d8a788fcf45df5bf4070ab2474c88d543a", "versionType": "git"}, {"lessThan": "b1afd40321f1c243cffbcf40ea7ca41aca87fa5e", "status": "affected", "version": "c0cfa2d8a788fcf45df5bf4070ab2474c88d543a", "versionType": "git"}, {"lessThan": "fcdd2242c0231032fc84e1404315c245ae56322a", "status": "affected", "version": "c0cfa2d8a788fcf45df5bf4070ab2474c88d543a", "versionType": "git"}]}, {"defaultStatus": "affected", "product": "Linux", "programFiles": ["net/vmw_vsock/af_vsock.c"], "repo": "https://git.kernel.org/pub/scm/linux/kernel/git/stable/linux.git", "vendor": "Linux", "versions": [{"status": "affected", "version": "5.5"}, {"lessThan": "5.5", "status": "unaffected", "version": "0", "versionType": "semver"}, {"lessThanOrEqual": "5.10.*", "status": "unaffected", "version": "5.10.235", "versionType": "semver"}, {"lessThanOrEqual": "5.15.*", "status": "unaffected", "version": "5.15.179", "versionType": "semver"}, {"lessThanOrEqual": "6.1.*", "status": "unaffected", "version": "6.1.131", "versionType": "semver"}, {"lessThanOrEqual": "6.6.*", "status": "unaffected", "version": "6.6.79", "versionType": "semver"}, {"lessThanOrEqual": "6.12.*", "status": "unaffected", "version": "6.12.16", "versionType": "semver"}, {"lessThanOrEqual": "6.13.*", "status": "unaffected", "version": "6.13.4", "versionType": "semver"}, {"lessThanOrEqual": "*", "status": "unaffected", "version": "6.14", "versionType": "original_commit_for_fix"}]}], "source": "416baaa9-dc9f-4396-8d5f-8c081fb06d67"}, {"affectedData": [{"defaultStatus": "unknown", "product": "SIMATIC S7-1500 CPU 1518-4 PN/DP MFP", "vendor": "Siemens", "versions": [{"lessThan": "*", "status": "affected", "version": "V3.1.5", "versionType": "custom"}]}, {"defaultStatus": "unknown", "product": "SIMATIC S7-1500 CPU 1518-4 PN/DP MFP", "vendor": "Siemens", "versions": [{"lessThan": "*", "status": "affected", "version": "V3.1.5", "versionType": "custom"}]}, {"defaultStatus": "unknown", "product": "SIMATIC S7-1500 CPU 1518F-4 PN/DP MFP", "vendor": "Siemens", "versions": [{"lessThan": "*", "status": "affected", "version": "V3.1.5", "versionType": "custom"}]}, {"defaultStatus": "unknown", "product": "SIMATIC S7-1500 CPU 1518F-4 PN/DP MFP", "vendor": "Siemens", "versions": [{"lessThan": "*", "status": "affected", "version": "V3.1.5", "versionType": "custom"}]}, {"defaultStatus": "unknown", "product": "SIMATIC S7-1500 TM MFP - GNU/Linux subsystem", "vendor": "Siemens", "versions": [{"lessThan": "*", "status": "affected", "version": "0", "versionType": "custom"}]}, {"defaultStatus": "unknown", "product": "SIMATIC S7-1500 TM MFP - GNU/Linux subsystem", "vendor": "Siemens", "versions": [{"lessThan": "*", "status": "affected", "version": "0", "versionType": "custom"}]}, {"defaultStatus": "unknown", "product": "SIPLUS S7-1500 CPU 1518-4 PN/DP MFP", "vendor": "Siemens", "versions": [{"lessThan": "*", "status": "affected", "version": "V3.1.5", "versionType": "custom"}]}], "source": "0b142b55-0307-4c5a-b3c9-f314f3fb7c5e"}], "configurations": [{"nodes": [{"cpeMatch": [{"criteria": "cpe:2.3:o:linux:linux_kernel:*:*:*:*:*:*:*:*", "matchCriteriaId": "545121FA-DE31-4154-9446-C2000FB4104D", "versionEndExcluding": "5.10.235", "versionStartIncluding": "5.5", "vulnerable": true}, {"criteria": "cpe:2.3:o:linux:linux_kernel:*:*:*:*:*:*:*:*", "matchCriteriaId": "C708062C-4E1B-465F-AE6D-C09C46400875", "versionEndExcluding": "5.15.179", "versionStartIncluding": "5.11", "vulnerable": true}, {"criteria": "cpe:2.3:o:linux:linux_kernel:*:*:*:*:*:*:*:*", "matchCriteriaId": "BA9C2DE3-D37C-46C6-8DCD-2EE509456E0B", "versionEndExcluding": "6.1.131", "versionStartIncluding": "5.16", "vulnerable": true}, {"criteria": "cpe:2.3:o:linux:linux_kernel:*:*:*:*:*:*:*:*", "matchCriteriaId": "B16AADE5-B2FD-4C14-B4E4-85E8EDAFE775", "versionEndExcluding": "6.6.79", "versionStartIncluding": "6.2", "vulnerable": true}, {"criteria": "cpe:2.3:o:linux:linux_kernel:*:*:*:*:*:*:*:*", "matchCriteriaId": "13C8DB18-FC60-425F-84E5-3EDDEC61B2FC", "versionEndExcluding": "6.12.16", "versionStartIncluding": "6.7", "vulnerable": true}, {"criteria": "cpe:2.3:o:linux:linux_kernel:*:*:*:*:*:*:*:*", "matchCriteriaId": "2A2093ED-74A9-43F9-AC72-50030F374EA4", "versionEndExcluding": "6.13.4", "versionStartIncluding": "6.13", "vulnerable": true}], "negate": false, "operator": "OR"}]}], "cveTags": [], "descriptions": [{"lang": "en", "value": "In the Linux kernel, the following vulnerability has been resolved:\n\nvsock: Keep the binding until socket destruction\n\nPreserve sockets bindings; this includes both resulting from an explicit\nbind() and those implicitly bound through autobind during connect().\n\nPrevents socket unbinding during a transport reassignment, which fixes a\nuse-after-free:\n\n 1. vsock_create() (refcnt=1) calls vsock_insert_unbound() (refcnt=2)\n 2. transport->release() calls vsock_remove_bound() without checking if\n sk was bound and moved to bound list (refcnt=1)\n 3. vsock_bind() assumes sk is in unbound list and before\n __vsock_insert_bound(vsock_bound_sockets()) calls\n __vsock_remove_bound() which does:\n list_del_init(&vsk->bound_table); // nop\n sock_put(&vsk->sk); // refcnt=0\n\nBUG: KASAN: slab-use-after-free in __vsock_bind+0x62e/0x730\nRead of size 4 at addr ffff88816b46a74c by task a.out/2057\n dump_stack_lvl+0x68/0x90\n print_report+0x174/0x4f6\n kasan_report+0xb9/0x190\n __vsock_bind+0x62e/0x730\n vsock_bind+0x97/0xe0\n __sys_bind+0x154/0x1f0\n __x64_sys_bind+0x6e/0xb0\n do_syscall_64+0x93/0x1b0\n entry_SYSCALL_64_after_hwframe+0x76/0x7e\n\nAllocated by task 2057:\n kasan_save_stack+0x1e/0x40\n kasan_save_track+0x10/0x30\n __kasan_slab_alloc+0x85/0x90\n kmem_cache_alloc_noprof+0x131/0x450\n sk_prot_alloc+0x5b/0x220\n sk_alloc+0x2c/0x870\n __vsock_create.constprop.0+0x2e/0xb60\n vsock_create+0xe4/0x420\n __sock_create+0x241/0x650\n __sys_socket+0xf2/0x1a0\n __x64_sys_socket+0x6e/0xb0\n do_syscall_64+0x93/0x1b0\n entry_SYSCALL_64_after_hwframe+0x76/0x7e\n\nFreed by task 2057:\n kasan_save_stack+0x1e/0x40\n kasan_save_track+0x10/0x30\n kasan_save_free_info+0x37/0x60\n __kasan_slab_free+0x4b/0x70\n kmem_cache_free+0x1a1/0x590\n __sk_destruct+0x388/0x5a0\n __vsock_bind+0x5e1/0x730\n vsock_bind+0x97/0xe0\n __sys_bind+0x154/0x1f0\n __x64_sys_bind+0x6e/0xb0\n do_syscall_64+0x93/0x1b0\n entry_SYSCALL_64_after_hwframe+0x76/0x7e\n\nrefcount_t: addition on 0; use-after-free.\nWARNING: CPU: 7 PID: 2057 at lib/refcount.c:25 refcount_warn_saturate+0xce/0x150\nRIP: 0010:refcount_warn_saturate+0xce/0x150\n __vsock_bind+0x66d/0x730\n vsock_bind+0x97/0xe0\n __sys_bind+0x154/0x1f0\n __x64_sys_bind+0x6e/0xb0\n do_syscall_64+0x93/0x1b0\n entry_SYSCALL_64_after_hwframe+0x76/0x7e\n\nrefcount_t: underflow; use-after-free.\nWARNING: CPU: 7 PID: 2057 at lib/refcount.c:28 refcount_warn_saturate+0xee/0x150\nRIP: 0010:refcount_warn_saturate+0xee/0x150\n vsock_remove_bound+0x187/0x1e0\n __vsock_release+0x383/0x4a0\n vsock_release+0x90/0x120\n __sock_release+0xa3/0x250\n sock_close+0x14/0x20\n __fput+0x359/0xa80\n task_work_run+0x107/0x1d0\n do_exit+0x847/0x2560\n do_group_exit+0xb8/0x250\n __x64_sys_exit_group+0x3a/0x50\n x64_sys_call+0xfec/0x14f0\n do_syscall_64+0x93/0x1b0\n entry_SYSCALL_64_after_hwframe+0x76/0x7e"}, {"lang": "es", "value": "En el kernel de Linux, se ha resuelto la siguiente vulnerabilidad: vsock: Mantener la vinculaci\u00f3n hasta la destrucci\u00f3n del socket Preservar las vinculaciones de los sockets; esto incluye tanto las resultantes de un bind() expl\u00edcito como las vinculadas impl\u00edcitamente a trav\u00e9s de autobind durante connect(). Evita la desvinculaci\u00f3n de sockets durante una reasignaci\u00f3n de transporte, lo que soluciona un use after free: 1. vsock_create() (refcnt=1) calls vsock_insert_unbound() (refcnt=2) 2. transport->release() calls vsock_remove_bound() without checking if sk was bound and moved to bound list (refcnt=1) 3. vsock_bind() assumes sk is in unbound list and before __vsock_insert_bound(vsock_bound_sockets()) calls __vsock_remove_bound() which does: list_del_init(&vsk->bound_table); // nop sock_put(&vsk->sk); // refcnt=0 BUG: KASAN: slab-use-after-free in __vsock_bind+0x62e/0x730 Read of size 4 at addr ffff88816b46a74c by task a.out/2057 dump_stack_lvl+0x68/0x90 print_report+0x174/0x4f6 kasan_report+0xb9/0x190 __vsock_bind+0x62e/0x730 vsock_bind+0x97/0xe0 __sys_bind+0x154/0x1f0 __x64_sys_bind+0x6e/0xb0 do_syscall_64+0x93/0x1b0 entry_SYSCALL_64_after_hwframe+0x76/0x7e Allocated by task 2057: kasan_save_stack+0x1e/0x40 kasan_save_track+0x10/0x30 __kasan_slab_alloc+0x85/0x90 kmem_cache_alloc_noprof+0x131/0x450 sk_prot_alloc+0x5b/0x220 sk_alloc+0x2c/0x870 __vsock_create.constprop.0+0x2e/0xb60 vsock_create+0xe4/0x420 __sock_create+0x241/0x650 __sys_socket+0xf2/0x1a0 __x64_sys_socket+0x6e/0xb0 do_syscall_64+0x93/0x1b0 entry_SYSCALL_64_after_hwframe+0x76/0x7e Freed by task 2057: kasan_save_stack+0x1e/0x40 kasan_save_track+0x10/0x30 kasan_save_free_info+0x37/0x60 __kasan_slab_free+0x4b/0x70 kmem_cache_free+0x1a1/0x590 __sk_destruct+0x388/0x5a0 __vsock_bind+0x5e1/0x730 vsock_bind+0x97/0xe0 __sys_bind+0x154/0x1f0 __x64_sys_bind+0x6e/0xb0 do_syscall_64+0x93/0x1b0 entry_SYSCALL_64_after_hwframe+0x76/0x7e refcount_t: addition on 0; use-after-free. WARNING: CPU: 7 PID: 2057 at lib/refcount.c:25 refcount_warn_saturate+0xce/0x150 RIP: 0010:refcount_warn_saturate+0xce/0x150 __vsock_bind+0x66d/0x730 vsock_bind+0x97/0xe0 __sys_bind+0x154/0x1f0 __x64_sys_bind+0x6e/0xb0 do_syscall_64+0x93/0x1b0 entry_SYSCALL_64_after_hwframe+0x76/0x7e refcount_t: underflow; use-after-free. WARNING: CPU: 7 PID: 2057 at lib/refcount.c:28 refcount_warn_saturate+0xee/0x150 RIP: 0010:refcount_warn_saturate+0xee/0x150 vsock_remove_bound+0x187/0x1e0 __vsock_release+0x383/0x4a0 vsock_release+0x90/0x120 __sock_release+0xa3/0x250 sock_close+0x14/0x20 __fput+0x359/0xa80 task_work_run+0x107/0x1d0 do_exit+0x847/0x2560 do_group_exit+0xb8/0x250 __x64_sys_exit_group+0x3a/0x50 x64_sys_call+0xfec/0x14f0 do_syscall_64+0x93/0x1b0 entry_SYSCALL_64_after_hwframe+0x76/0x7e "}], "id": "CVE-2025-21756", "lastModified": "2026-10-15T02:17:32.463", "metrics": {"cvssMetricV31": [{"cvssData": {"attackComplexity": "LOW", "attackVector": "LOCAL", "availabilityImpact": "HIGH", "baseScore": 7.8, "baseSeverity": "HIGH", "confidentialityImpact": "HIGH", "integrityImpact": "HIGH", "privilegesRequired": "LOW", "scope": "UNCHANGED", "userInteraction": "NONE", "vectorString": "CVSS:3.1/AV:L/AC:L/PR:L/UI:N/S:U/C:H/I:H/A:H", "version": "3.1"}, "exploitabilityScore": 1.8, "impactScore": 5.9, "source": "416baaa9-dc9f-4396-8d5f-8c081fb06d67", "type": "Secondary"}, {"cvssData": {"attackComplexity": "LOW", "attackVector": "LOCAL", "availabilityImpact": "HIGH", "baseScore": 7.8, "baseSeverity": "HIGH", "confidentialityImpact": "HIGH", "integrityImpact": "HIGH", "privilegesRequired": "LOW", "scope": "UNCHANGED", "userInteraction": "NONE", "vectorString": "CVSS:3.1/AV:L/AC:L/PR:L/UI:N/S:U/C:H/I:H/A:H", "version": "3.1"}, "exploitabilityScore": 1.8, "impactScore": 5.9, "source": "134c704f-9b21-4f2e-91b3-4a467353bcc0", "type": "Secondary"}], "ssvcV203": [{"source": "134c704f-9b21-4f2e-91b3-4a467353bcc0", "ssvcData": {"id": "CVE-2025-21756", "options": [{"exploitation": "poc"}, {"automatable": "no"}, {"technicalImpact": "total"}], "role": "CISA Coordinator", "timestamp": "2025-08-14T21:01:56.187542Z", "version": "2.0.3"}}]}, "published": "2025-02-27T03:15:16.250", "references": [{"source": "416baaa9-dc9f-4396-8d5f-8c081fb06d67", "tags": ["Patch"], "url": "https://git.kernel.org/stable/c/3f43540166128951cc1be7ab1ce6b7f05c670d8b"}, {"source": "416baaa9-dc9f-4396-8d5f-8c081fb06d67", "tags": ["Patch"], "url": "https://git.kernel.org/stable/c/42b33381e5e1f2b967dc4fb4221ddb9aaf10d197"}, {"source": "416baaa9-dc9f-4396-8d5f-8c081fb06d67", "tags": ["Patch"], "url": "https://git.kernel.org/stable/c/645ce25aa0e67895b11d89f27bb86c9d444c40f8"}, {"source": "416baaa9-dc9f-4396-8d5f-8c081fb06d67", "tags": ["Patch"], "url": "https://git.kernel.org/stable/c/b1afd40321f1c243cffbcf40ea7ca41aca87fa5e"}, {"source": "416baaa9-dc9f-4396-8d5f-8c081fb06d67", "tags": ["Patch"], "url": "https://git.kernel.org/stable/c/e48fcb403c2d0e574c19683f09399ab4cf67809c"}, {"source": "416baaa9-dc9f-4396-8d5f-8c081fb06d67", "tags": ["Patch"], "url": "https://git.kernel.org/stable/c/e7754d564579a5db9c5c9f74228df5d6dd6f1173"}, {"source": "416baaa9-dc9f-4396-8d5f-8c081fb06d67", "tags": ["Patch"], "url": "https://git.kernel.org/stable/c/fcdd2242c0231032fc84e1404315c245ae56322a"}, {"source": "af854a3a-2127-422b-91ae-364da2661108", "url": "https://lists.debian.org/debian-lts-announce/2025/05/msg00030.html"}, {"source": "af854a3a-2127-422b-91ae-364da2661108", "url": "https://lists.debian.org/debian-lts-announce/2025/05/msg00045.html"}, {"source": "0b142b55-0307-4c5a-b3c9-f314f3fb7c5e", "url": "https://cert-portal.siemens.com/productcert/html/ssa-082556.html"}, {"source": "0b142b55-0307-4c5a-b3c9-f314f3fb7c5e", "url": "https://cert-portal.siemens.com/productcert/html/ssa-265688.html"}, {"source": "0b142b55-0307-4c5a-b3c9-f314f3fb7c5e", "url": "https://cert-portal.siemens.com/productcert/html/ssa-784472.html"}], "sourceIdentifier": "416baaa9-dc9f-4396-8d5f-8c081fb06d67", "vulnStatus": "Modified", "weaknesses": [{"description": [{"lang": "en", "value": "CWE-416"}], "source": "134c704f-9b21-4f2e-91b3-4a467353bcc0", "type": "Secondary"}]}

{"affected_release": [{"advisory": "RHSA-2025:8137", "cpe": "cpe:/o:redhat:enterprise_linux:10.0", "package": "kernel-0:6.12.0-55.13.1.el10_0", "product_name": "Red Hat Enterprise Linux 10", "release_date": "2025-05-26T00:00:00Z"}, {"advisory": "RHSA-2025:8057", "cpe": "cpe:/a:redhat:enterprise_linux:8::nfv", "package": "kernel-rt-0:4.18.0-553.53.1.rt7.394.el8_10", "product_name": "Red Hat Enterprise Linux 8", "release_date": "2025-05-21T00:00:00Z"}, {"advisory": "RHSA-2025:8056", "cpe": "cpe:/o:redhat:enterprise_linux:8", "package": "kernel-0:4.18.0-553.53.1.el8_10", "product_name": "Red Hat Enterprise Linux 8", "release_date": "2025-05-21T00:00:00Z"}, {"advisory": "RHSA-2025:8345", "cpe": "cpe:/o:redhat:enterprise_linux:8", "package": "kpatch-patch", "product_name": "Red Hat Enterprise Linux 8", "release_date": "2025-06-02T00:00:00Z"}, {"advisory": "RHSA-2025:7901", "cpe": "cpe:/o:redhat:rhel_aus:8.4", "package": "kernel-0:4.18.0-305.157.1.el8_4", "product_name": "Red Hat Enterprise Linux 8.4 Advanced Mission Critical Update Support", "release_date": "2025-05-19T00:00:00Z"}, {"advisory": "RHSA-2025:7902", "cpe": "cpe:/a:redhat:rhel_tus:8.4::nfv", "package": "kernel-rt-0:4.18.0-305.157.1.rt7.234.el8_4", "product_name": "Red Hat Enterprise Linux 8.4 Telecommunications Update Service", "release_date": "2025-05-19T00:00:00Z"}, {"advisory": "RHSA-2025:7901", "cpe": "cpe:/o:redhat:rhel_tus:8.4", "package": "kernel-0:4.18.0-305.157.1.el8_4", "product_name": "Red Hat Enterprise Linux 8.4 Telecommunications Update Service", "release_date": "2025-05-19T00:00:00Z"}, {"advisory": "RHSA-2025:7901", "cpe": "cpe:/o:redhat:rhel_e4s:8.4", "package": "kernel-0:4.18.0-305.157.1.el8_4", "product_name": "Red Hat Enterprise Linux 8.4 Update Services for SAP Solutions", "release_date": "2025-05-19T00:00:00Z"}, {"advisory": "RHSA-2025:8348", "cpe": "cpe:/o:redhat:rhel_e4s:8.4", "package": "kpatch-patch", "product_name": "Red Hat Enterprise Linux 8.4 Update Services for SAP Solutions", "release_date": "2025-06-02T00:00:00Z"}, {"advisory": "RHSA-2025:7652", "cpe": "cpe:/o:redhat:rhel_aus:8.6", "package": "kernel-0:4.18.0-372.145.1.el8_6", "product_name": "Red Hat Enterprise Linux 8.6 Advanced Mission Critical Update Support", "release_date": "2025-05-15T00:00:00Z"}, {"advisory": "RHSA-2025:7652", "cpe": "cpe:/o:redhat:rhel_tus:8.6", "package": "kernel-0:4.18.0-372.145.1.el8_6", "product_name": "Red Hat Enterprise Linux 8.6 Telecommunications Update Service", "release_date": "2025-05-15T00:00:00Z"}, {"advisory": "RHSA-2025:7652", "cpe": "cpe:/o:redhat:rhel_e4s:8.6", "package": "kernel-0:4.18.0-372.145.1.el8_6", "product_name": "Red Hat Enterprise Linux 8.6 Update Services for SAP Solutions", "release_date": "2025-05-15T00:00:00Z"}, {"advisory": "RHSA-2025:8347", "cpe": "cpe:/o:redhat:rhel_e4s:8.6", "package": "kpatch-patch", "product_name": "Red Hat Enterprise Linux 8.6 Update Services for SAP Solutions", "release_date": "2025-06-02T00:00:00Z"}, {"advisory": "RHSA-2025:7682", "cpe": "cpe:/o:redhat:rhel_eus:8.8", "package": "kernel-0:4.18.0-477.97.1.el8_8", "product_name": "Red Hat Enterprise Linux 8.8 Extended Update Support", "release_date": "2025-05-15T00:00:00Z"}, {"advisory": "RHSA-2025:8346", "cpe": "cpe:/o:redhat:rhel_eus:8.8", "package": "kpatch-patch", "product_name": "Red Hat Enterprise Linux 8.8 Extended Update Support", "release_date": "2025-06-02T00:00:00Z"}, {"advisory": "RHSA-2025:7903", "cpe": "cpe:/a:redhat:enterprise_linux:9", "package": "kernel-0:5.14.0-570.17.1.el9_6", "product_name": "Red Hat Enterprise Linux 9", "release_date": "2025-05-19T00:00:00Z"}, {"advisory": "RHSA-2025:7903", "cpe": "cpe:/o:redhat:enterprise_linux:9", "package": "kernel-0:5.14.0-570.17.1.el9_6", "product_name": "Red Hat Enterprise Linux 9", "release_date": "2025-05-19T00:00:00Z"}, {"advisory": "RHSA-2025:7897", "cpe": "cpe:/a:redhat:rhel_e4s:9.0", "package": "kernel-0:5.14.0-70.132.1.el9_0", "product_name": "Red Hat Enterprise Linux 9.0 Update Services for SAP Solutions", "release_date": "2025-05-19T00:00:00Z"}, {"advisory": "RHSA-2025:7896", "cpe": "cpe:/a:redhat:rhel_e4s:9.0::nfv", "package": "kernel-rt-0:5.14.0-70.132.1.rt21.204.el9_0", "product_name": "Red Hat Enterprise Linux 9.0 Update Services for SAP Solutions", "release_date": "2025-05-19T00:00:00Z"}, {"advisory": "RHSA-2025:8344", "cpe": "cpe:/o:redhat:rhel_e4s:9.0", "package": "kpatch-patch", "product_name": "Red Hat Enterprise Linux 9.0 Update Services for SAP Solutions", "release_date": "2025-06-02T00:00:00Z"}, {"advisory": "RHSA-2025:7683", "cpe": "cpe:/a:redhat:rhel_eus:9.2", "package": "kernel-0:5.14.0-284.117.1.el9_2", "product_name": "Red Hat Enterprise Linux 9.2 Extended Update Support", "release_date": "2025-05-15T00:00:00Z"}, {"advisory": "RHSA-2025:7676", "cpe": "cpe:/a:redhat:rhel_eus:9.2::nfv", "package": "kernel-rt-0:5.14.0-284.117.1.rt14.402.el9_2", "product_name": "Red Hat Enterprise Linux 9.2 Extended Update Support", "release_date": "2025-05-15T00:00:00Z"}, {"advisory": "RHSA-2025:8343", "cpe": "cpe:/o:redhat:rhel_eus:9.2", "package": "kpatch-patch", "product_name": "Red Hat Enterprise Linux 9.2 Extended Update Support", "release_date": "2025-06-02T00:00:00Z"}, {"advisory": "RHSA-2025:8058", "cpe": "cpe:/a:redhat:rhel_eus:9.4", "package": "kernel-0:5.14.0-427.68.2.el9_4", "product_name": "Red Hat Enterprise Linux 9.4 Extended Update Support", "release_date": "2025-05-21T00:00:00Z"}, {"advisory": "RHSA-2025:8248", "cpe": "cpe:/a:redhat:rhel_eus:9.4", "package": "kernel-0:5.14.0-427.70.1.el9_4", "product_name": "Red Hat Enterprise Linux 9.4 Extended Update Support", "release_date": "2025-05-28T00:00:00Z"}, {"advisory": "RHSA-2025:8342", "cpe": "cpe:/o:redhat:rhel_eus:9.4", "package": "kpatch-patch", "product_name": "Red Hat Enterprise Linux 9.4 Extended Update Support", "release_date": "2025-06-02T00:00:00Z"}], "bugzilla": {"description": "kernel: vsock: Keep the binding until socket destruction", "id": "2348609", "url": "https://bugzilla.redhat.com/show_bug.cgi?id=2348609"}, "csaw": false, "cvss3": {"cvss3_base_score": "7.8", "cvss3_scoring_vector": "CVSS:3.1/AV:L/AC:L/PR:L/UI:N/S:U/C:H/I:H/A:H", "status": "verified"}, "cwe": "CWE-416", "details": ["In the Linux kernel, the following vulnerability has been resolved:\nvsock: Keep the binding until socket destruction\nPreserve sockets bindings; this includes both resulting from an explicit\nbind() and those implicitly bound through autobind during connect().\nPrevents socket unbinding during a transport reassignment, which fixes a\nuse-after-free:\n1. vsock_create() (refcnt=1) calls vsock_insert_unbound() (refcnt=2)\n2. transport->release() calls vsock_remove_bound() without checking if\nsk was bound and moved to bound list (refcnt=1)\n3. vsock_bind() assumes sk is in unbound list and before\n__vsock_insert_bound(vsock_bound_sockets()) calls\n__vsock_remove_bound() which does:\nlist_del_init(&vsk->bound_table); // nop\nsock_put(&vsk->sk); // refcnt=0\nBUG: KASAN: slab-use-after-free in __vsock_bind+0x62e/0x730\nRead of size 4 at addr ffff88816b46a74c by task a.out/2057\ndump_stack_lvl+0x68/0x90\nprint_report+0x174/0x4f6\nkasan_report+0xb9/0x190\n__vsock_bind+0x62e/0x730\nvsock_bind+0x97/0xe0\n__sys_bind+0x154/0x1f0\n__x64_sys_bind+0x6e/0xb0\ndo_syscall_64+0x93/0x1b0\nentry_SYSCALL_64_after_hwframe+0x76/0x7e\nAllocated by task 2057:\nkasan_save_stack+0x1e/0x40\nkasan_save_track+0x10/0x30\n__kasan_slab_alloc+0x85/0x90\nkmem_cache_alloc_noprof+0x131/0x450\nsk_prot_alloc+0x5b/0x220\nsk_alloc+0x2c/0x870\n__vsock_create.constprop.0+0x2e/0xb60\nvsock_create+0xe4/0x420\n__sock_create+0x241/0x650\n__sys_socket+0xf2/0x1a0\n__x64_sys_socket+0x6e/0xb0\ndo_syscall_64+0x93/0x1b0\nentry_SYSCALL_64_after_hwframe+0x76/0x7e\nFreed by task 2057:\nkasan_save_stack+0x1e/0x40\nkasan_save_track+0x10/0x30\nkasan_save_free_info+0x37/0x60\n__kasan_slab_free+0x4b/0x70\nkmem_cache_free+0x1a1/0x590\n__sk_destruct+0x388/0x5a0\n__vsock_bind+0x5e1/0x730\nvsock_bind+0x97/0xe0\n__sys_bind+0x154/0x1f0\n__x64_sys_bind+0x6e/0xb0\ndo_syscall_64+0x93/0x1b0\nentry_SYSCALL_64_after_hwframe+0x76/0x7e\nrefcount_t: addition on 0; use-after-free.\nWARNING: CPU: 7 PID: 2057 at lib/refcount.c:25 refcount_warn_saturate+0xce/0x150\nRIP: 0010:refcount_warn_saturate+0xce/0x150\n__vsock_bind+0x66d/0x730\nvsock_bind+0x97/0xe0\n__sys_bind+0x154/0x1f0\n__x64_sys_bind+0x6e/0xb0\ndo_syscall_64+0x93/0x1b0\nentry_SYSCALL_64_after_hwframe+0x76/0x7e\nrefcount_t: underflow; use-after-free.\nWARNING: CPU: 7 PID: 2057 at lib/refcount.c:28 refcount_warn_saturate+0xee/0x150\nRIP: 0010:refcount_warn_saturate+0xee/0x150\nvsock_remove_bound+0x187/0x1e0\n__vsock_release+0x383/0x4a0\nvsock_release+0x90/0x120\n__sock_release+0xa3/0x250\nsock_close+0x14/0x20\n__fput+0x359/0xa80\ntask_work_run+0x107/0x1d0\ndo_exit+0x847/0x2560\ndo_group_exit+0xb8/0x250\n__x64_sys_exit_group+0x3a/0x50\nx64_sys_call+0xfec/0x14f0\ndo_syscall_64+0x93/0x1b0\nentry_SYSCALL_64_after_hwframe+0x76/0x7e", "A flaw was found in the Linux kernel's virtual socket protocol network driver, where an improperly timed socket unbinding could result in a use-after-free issue. This flaw allows an attacker who can create and destroy arbitrary connections on virtual connections to read or modify system memory, potentially leading to an escalation of privileges or the compromise of sensitive data."], "mitigation": {"lang": "en:us", "value": "To mitigate this issue, prevent module vsock from being loaded. \nPlease see https://access.redhat.com/solutions/41278 for information on how to blacklist a kernel module to prevent it from loading automatically."}, "name": "CVE-2025-21756", "package_state": [{"cpe": "cpe:/o:redhat:enterprise_linux:6", "fix_state": "Not affected", "package_name": "kernel", "product_name": "Red Hat Enterprise Linux 6"}, {"cpe": "cpe:/o:redhat:enterprise_linux:7", "fix_state": "Not affected", "package_name": "kernel", "product_name": "Red Hat Enterprise Linux 7"}, {"cpe": "cpe:/o:redhat:enterprise_linux:7", "fix_state": "Not affected", "package_name": "kernel-rt", "product_name": "Red Hat Enterprise Linux 7"}, {"cpe": "cpe:/o:redhat:enterprise_linux:9", "fix_state": "Affected", "package_name": "kernel-rt", "product_name": "Red Hat Enterprise Linux 9"}], "public_date": "2025-02-27T00:00:00Z", "references": ["https://www.cve.org/CVERecord?id=CVE-2025-21756\nhttps://nvd.nist.gov/vuln/detail/CVE-2025-21756\nhttps://lore.kernel.org/linux-cve-announce/2025022603-CVE-2025-21756-5e09@gregkh/T"], "statement": "If Virtual Socket Protocol is being used during connection, or during a transport reassignment, a use-after-free could happen. The local user is supposed to call the bind() function when opening the connection.", "threat_severity": "Important"}

{"analysis": {"en": {"generated_at": "2026-04-28T03:34:27.495173+00:00", "value": {"mitigation_remediation": ["Apply the vendor\u2019s kernel update that includes the fix for CVE\u20112025\u201121756.", "If an immediate update is unavailable, disable the vsock kernel module or block vsock socket creation using firewall or network policy controls.", "Monitor system logs for anomalous vsock activity and apply SELinux or AppArmor hardening to restrict socket creation privileges."], "summary": {"action": "Update Kernel", "impact": "Privilege Escalation"}, "threat_synthesis": {"affected_systems": "The flaw affects all Linux kernel builds that incorporate the vsock module, including Red Hat Enterprise Linux\u202f8,\u202f9,\u202f10 and related derivatives, as well as other distributions using the upstream kernel. No specific version range is listed, so any kernel that has not applied the recent patch may be affected.", "description_and_impact": "The vulnerability is a use\u2011after\u2011free flaw in the Linux kernel\u2019s vsock socket code (CWE\u2011416). It can cause kernel memory corruption when a socket is unbound after a transport reassignment, potentially allowing an attacker to read or modify memory or execute code with kernel privileges.", "risk_and_exploitability": "The CVSS score of 7.8 indicates a high risk, while an EPSS score of <1\u202f% and absence from the CISA KEV catalog suggest exploitation is unlikely at present. The flaw would likely be triggered by local actions that involve creating or manipulating vsock connections; thus, updating the kernel or limiting vsock usage mitigates the threat."}}}}, "created": "2026-04-28T03:45:20.280299+00:00", "updated": "2026-04-28T03:45:20.280310+00:00", "vendors": []}