CVE-2025-38527

{"dataType": "CVE_RECORD", "dataVersion": "5.2", "cveMetadata": {"cveId": "CVE-2025-38527", "assignerOrgId": "416baaa9-dc9f-4396-8d5f-8c081fb06d67", "state": "PUBLISHED", "assignerShortName": "Linux", "dateReserved": "2025-04-16T04:51:24.023Z", "datePublished": "2025-08-16T11:12:20.843Z", "dateUpdated": "2026-10-15T21:52:18.718Z"}, "containers": {"cna": {"providerMetadata": {"orgId": "416baaa9-dc9f-4396-8d5f-8c081fb06d67", "shortName": "Linux", "dateUpdated": "2026-08-05T12:02:40.247Z"}, "descriptions": [{"lang": "en", "value": "In the Linux kernel, the following vulnerability has been resolved:\n\nsmb: client: fix use-after-free in cifs_oplock_break\n\nA race condition can occur in cifs_oplock_break() leading to a\nuse-after-free of the cinode structure when unmounting:\n\n cifs_oplock_break()\n _cifsFileInfo_put(cfile)\n cifsFileInfo_put_final()\n cifs_sb_deactive()\n [last ref, start releasing sb]\n kill_sb()\n kill_anon_super()\n generic_shutdown_super()\n evict_inodes()\n dispose_list()\n evict()\n destroy_inode()\n call_rcu(&inode->i_rcu, i_callback)\n spin_lock(&cinode->open_file_lock) <- OK\n [later] i_callback()\n cifs_free_inode()\n kmem_cache_free(cinode)\n spin_unlock(&cinode->open_file_lock) <- UAF\n cifs_done_oplock_break(cinode) <- UAF\n\nThe issue occurs when umount has already released its reference to the\nsuperblock. When _cifsFileInfo_put() calls cifs_sb_deactive(), this\nreleases the last reference, triggering the immediate cleanup of all\ninodes under RCU. However, cifs_oplock_break() continues to access the\ncinode after this point, resulting in use-after-free.\n\nFix this by holding an extra reference to the superblock during the\nentire oplock break operation. This ensures that the superblock and\nits inodes remain valid until the oplock break completes."}], "metrics": [{"cvssV3_1": {"version": "3.1", "vectorString": "CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:H/I:H/A:H", "baseScore": 9.8, "baseSeverity": "CRITICAL"}, "scenarios": [{"lang": "en", "value": "AV:N - The freeing side is driven entirely by a remote SMB peer \u2014 `smb2_is_valid_oplock_break()` (fs/smb/client/smb2misc.c:712) parses unsolicited SMB2 OPLOCK_BREAK/LEASE_BREAK PDUs off the socket and queues `cifs_oplock_break()`, and the server also controls the stalls (`filemap_fdatawrite`/`fdatawait`, tree disconnect) that widen the window. A malicious, compromised, or on-path SMB server (signing is frequently absent) reaches this over the network or WAN.\nAC:L - This is not a tight race: the attacker parks the worker indefinitely by refusing to complete writeback, so whenever the unmount lands the worker deterministically holds the last superblock reference, and it then releases the stall at a time of its choosing. The intervening `kill_sb` network round trips guarantee the RCU grace period elapses before `cifs_done_oplock_break(cinode)`, making the use-after-free reliable and infinitely repeatable.\nPR:N - The attacker is the remote SMB server or an on-path attacker and holds no credentials, account, or capability on the victim client; oplock/lease breaks are unsolicited server-to-client notifications handled by the demultiplex thread. Client-side mount configuration is a deployment condition, not an attacker privilege.\nUI:N - The CIFS mount is a standing deployment condition (fstab/autofs/systemd `.automount`/pam_mount), and the required unmount happens automatically on idle expiry, logout, or attacker-induced link loss \u2014 no person participates. Because the attacker can hold the oplock-break worker parked indefinitely, it need only wait for that automatic teardown rather than race any user action.\nS:U - The use-after-free corrupts kernel slab memory (`cifs_inode_cache`) within the same kernel security authority as the vulnerable CIFS client code. No VM, IOMMU, or sandbox boundary is crossed.\nC:H - When the freed `openFileList` head is groomed to appear non-empty, `smb2_oplock_response()` reads `cinode->lease_key` out of freed slab memory and transmits it to the attacker's server in the break acknowledgement \u2014 a repeatable kernel-heap infoleak \u2014 and dereferences `cinode->netfs.inode.i_sb->s_fs_info` from the dead object. Controlling the reallocated object escalates this to arbitrary kernel memory disclosure.\nI:H - `spin_unlock(&cinode->open_file_lock)` and `cifs_done_oplock_break()`'s `clear_bit(CIFS_INODE_PENDING_OPLOCK_BREAK, &cinode->flags)` are out-of-lifetime writes at fixed offsets into whatever object reclaims the freed `cifsInodeInfo`, and the attacker can refill that slab with inodes whose fields come from its own server responses. Combined with the wild `i_sb->s_fs_info` dereference, this is the standard heap-grooming path to a write primitive and control-flow hijack.\nA:H - Operating on the freed `cifsInodeInfo` \u2014 spinlock manipulation, list traversal, and a bit clear on released slab memory \u2014 produces KASAN splats, slab corruption, and oops/panic, as reported in kernel.org bugzilla #220309. The remote server can retrigger the sequence at will on every mount cycle."}]}], "affected": [{"product": "Linux", "vendor": "Linux", "defaultStatus": "unaffected", "repo": "https://git.kernel.org/pub/scm/linux/kernel/git/stable/linux.git", "programFiles": ["fs/smb/client/file.c"], "versions": [{"version": "b98749cac4a695f084a5ff076f4510b23e353ecd", "lessThan": "4256a483fe58af66a46cbf3dc48ff26e580d3308", "status": "affected", "versionType": "git"}, {"version": "b98749cac4a695f084a5ff076f4510b23e353ecd", "lessThan": "0a4eec84d4d2c4085d4ed8630fd74e4b39033c1b", "status": "affected", "versionType": "git"}, {"version": "b98749cac4a695f084a5ff076f4510b23e353ecd", "lessThan": "2baaf5bbab2ac474c4f92c10fcb3310f824db995", "status": "affected", "versionType": "git"}, {"version": "b98749cac4a695f084a5ff076f4510b23e353ecd", "lessThan": "09bce2138a30ef10d8821c8c3f73a4ab7a5726bc", "status": "affected", "versionType": "git"}, {"version": "b98749cac4a695f084a5ff076f4510b23e353ecd", "lessThan": "da11bd4b697b393a207f19a2ed7d382a811a3ddc", "status": "affected", "versionType": "git"}, {"version": "b98749cac4a695f084a5ff076f4510b23e353ecd", "lessThan": "705c79101ccf9edea5a00d761491a03ced314210", "status": "affected", "versionType": "git"}, {"version": "2429fcf06d3cb962693868ab0a927c9038f12a2d", "status": "affected", "versionType": "git"}, {"version": "1ee4f2d7cdcd4508cc3cbe3b2622d7177b89da12", "status": "affected", "versionType": "git"}, {"version": "53fc31a4853e30d6e8f142b824f724da27ff3e40", "status": "affected", "versionType": "git"}, {"version": "8092ecc306d81186a64cda42411121f4d35aaff4", "status": "affected", "versionType": "git"}, {"version": "ebac4d0adf68f8962bd82fcf483936edd6ec095b", "status": "affected", "versionType": "git"}, {"version": "3.16.72", "lessThan": "3.17", "status": "affected", "versionType": "semver"}, {"version": "4.9.171", "lessThan": "4.10", "status": "affected", "versionType": "semver"}, {"version": "4.14.114", "lessThan": "4.15", "status": "affected", "versionType": "semver"}, {"version": "4.19.37", "lessThan": "4.20", "status": "affected", "versionType": "semver"}, {"version": "5.0.10", "lessThan": "5.1", "status": "affected", "versionType": "semver"}]}, {"product": "Linux", "vendor": "Linux", "defaultStatus": "affected", "repo": "https://git.kernel.org/pub/scm/linux/kernel/git/stable/linux.git", "programFiles": ["fs/smb/client/file.c"], "versions": [{"version": "5.1", "status": "affected"}, {"version": "0", "lessThan": "5.1", "status": "unaffected", "versionType": "semver"}, {"version": "5.15.190", "lessThanOrEqual": "5.15.*", "status": "unaffected", "versionType": "semver"}, {"version": "6.1.147", "lessThanOrEqual": "6.1.*", "status": "unaffected", "versionType": "semver"}, {"version": "6.6.100", "lessThanOrEqual": "6.6.*", "status": "unaffected", "versionType": "semver"}, {"version": "6.12.40", "lessThanOrEqual": "6.12.*", "status": "unaffected", "versionType": "semver"}, {"version": "6.15.8", "lessThanOrEqual": "6.15.*", "status": "unaffected", "versionType": "semver"}, {"version": "6.16", "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": "5.1", "versionEndExcluding": "5.15.190"}, {"vulnerable": true, "criteria": "cpe:2.3:o:linux:linux_kernel:*:*:*:*:*:*:*:*", "versionStartIncluding": "5.1", "versionEndExcluding": "6.1.147"}, {"vulnerable": true, "criteria": "cpe:2.3:o:linux:linux_kernel:*:*:*:*:*:*:*:*", "versionStartIncluding": "5.1", "versionEndExcluding": "6.6.100"}, {"vulnerable": true, "criteria": "cpe:2.3:o:linux:linux_kernel:*:*:*:*:*:*:*:*", "versionStartIncluding": "5.1", "versionEndExcluding": "6.12.40"}, {"vulnerable": true, "criteria": "cpe:2.3:o:linux:linux_kernel:*:*:*:*:*:*:*:*", "versionStartIncluding": "5.1", "versionEndExcluding": "6.15.8"}, {"vulnerable": true, "criteria": "cpe:2.3:o:linux:linux_kernel:*:*:*:*:*:*:*:*", "versionStartIncluding": "5.1", "versionEndExcluding": "6.16"}, {"vulnerable": true, "criteria": "cpe:2.3:o:linux:linux_kernel:*:*:*:*:*:*:*:*", "versionStartIncluding": "3.16.72"}, {"vulnerable": true, "criteria": "cpe:2.3:o:linux:linux_kernel:*:*:*:*:*:*:*:*", "versionStartIncluding": "4.9.171"}, {"vulnerable": true, "criteria": "cpe:2.3:o:linux:linux_kernel:*:*:*:*:*:*:*:*", "versionStartIncluding": "4.14.114"}, {"vulnerable": true, "criteria": "cpe:2.3:o:linux:linux_kernel:*:*:*:*:*:*:*:*", "versionStartIncluding": "4.19.37"}, {"vulnerable": true, "criteria": "cpe:2.3:o:linux:linux_kernel:*:*:*:*:*:*:*:*", "versionStartIncluding": "5.0.10"}]}]}], "references": [{"url": "https://git.kernel.org/stable/c/4256a483fe58af66a46cbf3dc48ff26e580d3308"}, {"url": "https://git.kernel.org/stable/c/0a4eec84d4d2c4085d4ed8630fd74e4b39033c1b"}, {"url": "https://git.kernel.org/stable/c/2baaf5bbab2ac474c4f92c10fcb3310f824db995"}, {"url": "https://git.kernel.org/stable/c/09bce2138a30ef10d8821c8c3f73a4ab7a5726bc"}, {"url": "https://git.kernel.org/stable/c/da11bd4b697b393a207f19a2ed7d382a811a3ddc"}, {"url": "https://git.kernel.org/stable/c/705c79101ccf9edea5a00d761491a03ced314210"}], "title": "smb: client: fix use-after-free in cifs_oplock_break", "x_generator": {"engine": "bippy-1.2.0"}}, "adp": [{"title": "CVE Program Container", "references": [{"url": "https://lists.debian.org/debian-lts-announce/2025/10/msg00008.html"}], "providerMetadata": {"orgId": "af854a3a-2127-422b-91ae-364da2661108", "shortName": "CVE", "dateUpdated": "2025-11-03T17:39:23.898Z"}}, {"metrics": [{"other": {"type": "ssvc", "content": {"id": "CVE-2025-38527", "role": "CISA Coordinator", "options": [{"Exploitation": "none"}, {"Automatable": "yes"}, {"Technical Impact": "total"}], "version": "2.0.3", "timestamp": "2026-10-15T21:51:26.435108Z"}}}], "title": "CISA ADP Vulnrichment", "providerMetadata": {"orgId": "134c704f-9b21-4f2e-91b3-4a467353bcc0", "shortName": "CISA-ADP", "dateUpdated": "2026-10-15T21:52:18.718Z"}}]}}

{"dataType": "CVE_RECORD", "containers": {"adp": [{"title": "CVE Program Container", "references": [{"url": "https://lists.debian.org/debian-lts-announce/2025/10/msg00008.html"}], "providerMetadata": {"orgId": "af854a3a-2127-422b-91ae-364da2661108", "shortName": "CVE", "dateUpdated": "2025-11-03T17:39:23.898Z"}}, {"title": "CISA ADP Vulnrichment", "metrics": [{"other": {"type": "ssvc", "content": {"id": "CVE-2025-38527", "role": "CISA Coordinator", "options": [{"Exploitation": "none"}, {"Automatable": "yes"}, {"Technical Impact": "total"}], "version": "2.0.3", "timestamp": "2026-10-15T21:51:26.435108Z"}}}], "providerMetadata": {"orgId": "134c704f-9b21-4f2e-91b3-4a467353bcc0", "shortName": "CISA-ADP", "dateUpdated": "2026-10-15T21:51:27.009Z"}}], "cna": {"title": "smb: client: fix use-after-free in cifs_oplock_break", "metrics": [{"cvssV3_1": {"version": "3.1", "baseScore": 9.8, "baseSeverity": "CRITICAL", "vectorString": "CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:H/I:H/A:H"}, "scenarios": [{"lang": "en", "value": "AV:N - The freeing side is driven entirely by a remote SMB peer \u2014 `smb2_is_valid_oplock_break()` (fs/smb/client/smb2misc.c:712) parses unsolicited SMB2 OPLOCK_BREAK/LEASE_BREAK PDUs off the socket and queues `cifs_oplock_break()`, and the server also controls the stalls (`filemap_fdatawrite`/`fdatawait`, tree disconnect) that widen the window. A malicious, compromised, or on-path SMB server (signing is frequently absent) reaches this over the network or WAN.\nAC:L - This is not a tight race: the attacker parks the worker indefinitely by refusing to complete writeback, so whenever the unmount lands the worker deterministically holds the last superblock reference, and it then releases the stall at a time of its choosing. The intervening `kill_sb` network round trips guarantee the RCU grace period elapses before `cifs_done_oplock_break(cinode)`, making the use-after-free reliable and infinitely repeatable.\nPR:N - The attacker is the remote SMB server or an on-path attacker and holds no credentials, account, or capability on the victim client; oplock/lease breaks are unsolicited server-to-client notifications handled by the demultiplex thread. Client-side mount configuration is a deployment condition, not an attacker privilege.\nUI:N - The CIFS mount is a standing deployment condition (fstab/autofs/systemd `.automount`/pam_mount), and the required unmount happens automatically on idle expiry, logout, or attacker-induced link loss \u2014 no person participates. Because the attacker can hold the oplock-break worker parked indefinitely, it need only wait for that automatic teardown rather than race any user action.\nS:U - The use-after-free corrupts kernel slab memory (`cifs_inode_cache`) within the same kernel security authority as the vulnerable CIFS client code. No VM, IOMMU, or sandbox boundary is crossed.\nC:H - When the freed `openFileList` head is groomed to appear non-empty, `smb2_oplock_response()` reads `cinode->lease_key` out of freed slab memory and transmits it to the attacker's server in the break acknowledgement \u2014 a repeatable kernel-heap infoleak \u2014 and dereferences `cinode->netfs.inode.i_sb->s_fs_info` from the dead object. Controlling the reallocated object escalates this to arbitrary kernel memory disclosure.\nI:H - `spin_unlock(&cinode->open_file_lock)` and `cifs_done_oplock_break()`'s `clear_bit(CIFS_INODE_PENDING_OPLOCK_BREAK, &cinode->flags)` are out-of-lifetime writes at fixed offsets into whatever object reclaims the freed `cifsInodeInfo`, and the attacker can refill that slab with inodes whose fields come from its own server responses. Combined with the wild `i_sb->s_fs_info` dereference, this is the standard heap-grooming path to a write primitive and control-flow hijack.\nA:H - Operating on the freed `cifsInodeInfo` \u2014 spinlock manipulation, list traversal, and a bit clear on released slab memory \u2014 produces KASAN splats, slab corruption, and oops/panic, as reported in kernel.org bugzilla #220309. The remote server can retrigger the sequence at will on every mount cycle."}]}], "affected": [{"repo": "https://git.kernel.org/pub/scm/linux/kernel/git/stable/linux.git", "vendor": "Linux", "product": "Linux", "versions": [{"status": "affected", "version": "b98749cac4a695f084a5ff076f4510b23e353ecd", "lessThan": "4256a483fe58af66a46cbf3dc48ff26e580d3308", "versionType": "git"}, {"status": "affected", "version": "b98749cac4a695f084a5ff076f4510b23e353ecd", "lessThan": "0a4eec84d4d2c4085d4ed8630fd74e4b39033c1b", "versionType": "git"}, {"status": "affected", "version": "b98749cac4a695f084a5ff076f4510b23e353ecd", "lessThan": "2baaf5bbab2ac474c4f92c10fcb3310f824db995", "versionType": "git"}, {"status": "affected", "version": "b98749cac4a695f084a5ff076f4510b23e353ecd", "lessThan": "09bce2138a30ef10d8821c8c3f73a4ab7a5726bc", "versionType": "git"}, {"status": "affected", "version": "b98749cac4a695f084a5ff076f4510b23e353ecd", "lessThan": "da11bd4b697b393a207f19a2ed7d382a811a3ddc", "versionType": "git"}, {"status": "affected", "version": "b98749cac4a695f084a5ff076f4510b23e353ecd", "lessThan": "705c79101ccf9edea5a00d761491a03ced314210", "versionType": "git"}, {"status": "affected", "version": "2429fcf06d3cb962693868ab0a927c9038f12a2d", "versionType": "git"}, {"status": "affected", "version": "1ee4f2d7cdcd4508cc3cbe3b2622d7177b89da12", "versionType": "git"}, {"status": "affected", "version": "53fc31a4853e30d6e8f142b824f724da27ff3e40", "versionType": "git"}, {"status": "affected", "version": "8092ecc306d81186a64cda42411121f4d35aaff4", "versionType": "git"}, {"status": "affected", "version": "ebac4d0adf68f8962bd82fcf483936edd6ec095b", "versionType": "git"}, {"status": "affected", "version": "3.16.72", "lessThan": "3.17", "versionType": "semver"}, {"status": "affected", "version": "4.9.171", "lessThan": "4.10", "versionType": "semver"}, {"status": "affected", "version": "4.14.114", "lessThan": "4.15", "versionType": "semver"}, {"status": "affected", "version": "4.19.37", "lessThan": "4.20", "versionType": "semver"}, {"status": "affected", "version": "5.0.10", "lessThan": "5.1", "versionType": "semver"}], "programFiles": ["fs/smb/client/file.c"], "defaultStatus": "unaffected"}, {"repo": "https://git.kernel.org/pub/scm/linux/kernel/git/stable/linux.git", "vendor": "Linux", "product": "Linux", "versions": [{"status": "affected", "version": "5.1"}, {"status": "unaffected", "version": "0", "lessThan": "5.1", "versionType": "semver"}, {"status": "unaffected", "version": "5.15.190", "versionType": "semver", "lessThanOrEqual": "5.15.*"}, {"status": "unaffected", "version": "6.1.147", "versionType": "semver", "lessThanOrEqual": "6.1.*"}, {"status": "unaffected", "version": "6.6.100", "versionType": "semver", "lessThanOrEqual": "6.6.*"}, {"status": "unaffected", "version": "6.12.40", "versionType": "semver", "lessThanOrEqual": "6.12.*"}, {"status": "unaffected", "version": "6.15.8", "versionType": "semver", "lessThanOrEqual": "6.15.*"}, {"status": "unaffected", "version": "6.16", "versionType": "original_commit_for_fix", "lessThanOrEqual": "*"}], "programFiles": ["fs/smb/client/file.c"], "defaultStatus": "affected"}], "references": [{"url": "https://git.kernel.org/stable/c/4256a483fe58af66a46cbf3dc48ff26e580d3308"}, {"url": "https://git.kernel.org/stable/c/0a4eec84d4d2c4085d4ed8630fd74e4b39033c1b"}, {"url": "https://git.kernel.org/stable/c/2baaf5bbab2ac474c4f92c10fcb3310f824db995"}, {"url": "https://git.kernel.org/stable/c/09bce2138a30ef10d8821c8c3f73a4ab7a5726bc"}, {"url": "https://git.kernel.org/stable/c/da11bd4b697b393a207f19a2ed7d382a811a3ddc"}, {"url": "https://git.kernel.org/stable/c/705c79101ccf9edea5a00d761491a03ced314210"}], "x_generator": {"engine": "bippy-1.2.0"}, "descriptions": [{"lang": "en", "value": "In the Linux kernel, the following vulnerability has been resolved:\n\nsmb: client: fix use-after-free in cifs_oplock_break\n\nA race condition can occur in cifs_oplock_break() leading to a\nuse-after-free of the cinode structure when unmounting:\n\n cifs_oplock_break()\n _cifsFileInfo_put(cfile)\n cifsFileInfo_put_final()\n cifs_sb_deactive()\n [last ref, start releasing sb]\n kill_sb()\n kill_anon_super()\n generic_shutdown_super()\n evict_inodes()\n dispose_list()\n evict()\n destroy_inode()\n call_rcu(&inode->i_rcu, i_callback)\n spin_lock(&cinode->open_file_lock) <- OK\n [later] i_callback()\n cifs_free_inode()\n kmem_cache_free(cinode)\n spin_unlock(&cinode->open_file_lock) <- UAF\n cifs_done_oplock_break(cinode) <- UAF\n\nThe issue occurs when umount has already released its reference to the\nsuperblock. When _cifsFileInfo_put() calls cifs_sb_deactive(), this\nreleases the last reference, triggering the immediate cleanup of all\ninodes under RCU. However, cifs_oplock_break() continues to access the\ncinode after this point, resulting in use-after-free.\n\nFix this by holding an extra reference to the superblock during the\nentire oplock break operation. This ensures that the superblock and\nits inodes remain valid until the oplock break completes."}], "cpeApplicability": [{"nodes": [{"negate": false, "cpeMatch": [{"criteria": "cpe:2.3:o:linux:linux_kernel:*:*:*:*:*:*:*:*", "vulnerable": true, "versionEndExcluding": "5.15.190", "versionStartIncluding": "5.1"}, {"criteria": "cpe:2.3:o:linux:linux_kernel:*:*:*:*:*:*:*:*", "vulnerable": true, "versionEndExcluding": "6.1.147", "versionStartIncluding": "5.1"}, {"criteria": "cpe:2.3:o:linux:linux_kernel:*:*:*:*:*:*:*:*", "vulnerable": true, "versionEndExcluding": "6.6.100", "versionStartIncluding": "5.1"}, {"criteria": "cpe:2.3:o:linux:linux_kernel:*:*:*:*:*:*:*:*", "vulnerable": true, "versionEndExcluding": "6.12.40", "versionStartIncluding": "5.1"}, {"criteria": "cpe:2.3:o:linux:linux_kernel:*:*:*:*:*:*:*:*", "vulnerable": true, "versionEndExcluding": "6.15.8", "versionStartIncluding": "5.1"}, {"criteria": "cpe:2.3:o:linux:linux_kernel:*:*:*:*:*:*:*:*", "vulnerable": true, "versionEndExcluding": "6.16", "versionStartIncluding": "5.1"}, {"criteria": "cpe:2.3:o:linux:linux_kernel:*:*:*:*:*:*:*:*", "vulnerable": true, "versionStartIncluding": "3.16.72"}, {"criteria": "cpe:2.3:o:linux:linux_kernel:*:*:*:*:*:*:*:*", "vulnerable": true, "versionStartIncluding": "4.9.171"}, {"criteria": "cpe:2.3:o:linux:linux_kernel:*:*:*:*:*:*:*:*", "vulnerable": true, "versionStartIncluding": "4.14.114"}, {"criteria": "cpe:2.3:o:linux:linux_kernel:*:*:*:*:*:*:*:*", "vulnerable": true, "versionStartIncluding": "4.19.37"}, {"criteria": "cpe:2.3:o:linux:linux_kernel:*:*:*:*:*:*:*:*", "vulnerable": true, "versionStartIncluding": "5.0.10"}], "operator": "OR"}]}], "providerMetadata": {"orgId": "416baaa9-dc9f-4396-8d5f-8c081fb06d67", "shortName": "Linux", "dateUpdated": "2026-08-05T12:02:40.247Z"}}}, "cveMetadata": {"cveId": "CVE-2025-38527", "state": "PUBLISHED", "dateUpdated": "2026-10-15T21:52:18.718Z", "dateReserved": "2025-04-16T04:51:24.023Z", "assignerOrgId": "416baaa9-dc9f-4396-8d5f-8c081fb06d67", "datePublished": "2025-08-16T11:12:20.843Z", "assignerShortName": "Linux"}, "dataVersion": "5.2"}

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has been resolved:\n\nsmb: client: fix use-after-free in cifs_oplock_break\n\nA race condition can occur in cifs_oplock_break() leading to a\nuse-after-free of the cinode structure when unmounting:\n\n cifs_oplock_break()\n _cifsFileInfo_put(cfile)\n cifsFileInfo_put_final()\n cifs_sb_deactive()\n [last ref, start releasing sb]\n kill_sb()\n kill_anon_super()\n generic_shutdown_super()\n evict_inodes()\n dispose_list()\n evict()\n destroy_inode()\n call_rcu(&inode->i_rcu, i_callback)\n spin_lock(&cinode->open_file_lock) <- OK\n [later] i_callback()\n cifs_free_inode()\n kmem_cache_free(cinode)\n spin_unlock(&cinode->open_file_lock) <- UAF\n cifs_done_oplock_break(cinode) <- UAF\n\nThe issue occurs when umount has already released its reference to the\nsuperblock. When _cifsFileInfo_put() calls cifs_sb_deactive(), this\nreleases the last reference, triggering the immediate cleanup of all\ninodes under RCU. However, cifs_oplock_break() continues to access the\ncinode after this point, resulting in use-after-free.\n\nFix this by holding an extra reference to the superblock during the\nentire oplock break operation. This ensures that the superblock and\nits inodes remain valid until the oplock break completes."}, {"lang": "es", "value": "En el kernel de Linux, se ha resuelto la siguiente vulnerabilidad: smb: cliente: correcci\u00f3n duse after free en cifs_oplock_break. Puede producirse una condici\u00f3n de ejecuci\u00f3n en cifs_oplock_break() que provoca un use after free de la estructura cinode al desmontar: cifs_oplock_break() _cifsFileInfo_put(cfile) cifsFileInfo_put_final() cifs_sb_deactive() [\u00faltima referencia, iniciar la liberaci\u00f3n de sb] kill_sb() kill_anon_super() generic_shutdown_super() evict_inodes() dispose_list() evict() destroy_inode() call_rcu(&amp;inode-&gt;i_rcu, i_callback) spin_lock(&amp;cinode-&gt;open_file_lock) &lt;- OK [m\u00e1s tarde] i_callback() cifs_free_inode() kmem_cache_free(cinode) spin_unlock(&amp;cinode-&gt;open_file_lock) &lt;- UAF cifs_done_oplock_break(cinode) &lt;- UAF El problema ocurre cuando umount ya ha liberado su referencia al superbloque. Cuando _cifsFileInfo_put() llama a cifs_sb_deactive(), se libera la \u00faltima referencia, lo que desencadena la limpieza inmediata de todos los inodos bajo RCU. Sin embargo, cifs_oplock_break() contin\u00faa accediendo al cinode despu\u00e9s de este punto, lo que resulta en un use after free. Para solucionar esto, mantenga una referencia adicional al superbloque durante toda la operaci\u00f3n de ruptura del oplock. Esto garantiza que el superbloque y sus inodos sigan siendo v\u00e1lidos hasta que se complete la ruptura del oplock."}], "id": "CVE-2025-38527", "lastModified": "2026-10-15T22:18:44.583", "metrics": {"cvssMetricV31": [{"cvssData": {"attackComplexity": "LOW", "attackVector": "NETWORK", "availabilityImpact": "HIGH", "baseScore": 9.8, "baseSeverity": "CRITICAL", "confidentialityImpact": "HIGH", "integrityImpact": "HIGH", "privilegesRequired": "NONE", "scope": "UNCHANGED", "userInteraction": "NONE", "vectorString": "CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:H/I:H/A:H", "version": "3.1"}, "exploitabilityScore": 3.9, "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": "nvd@nist.gov", "type": "Primary"}], "ssvcV203": [{"source": "134c704f-9b21-4f2e-91b3-4a467353bcc0", "ssvcData": {"id": "CVE-2025-38527", "options": [{"exploitation": "none"}, {"automatable": "yes"}, {"technicalImpact": "total"}], "role": "CISA Coordinator", "timestamp": "2026-10-15T21:51:26.435108Z", "version": "2.0.3"}}]}, "published": "2025-08-16T12:15:28.183", "references": [{"source": "416baaa9-dc9f-4396-8d5f-8c081fb06d67", "tags": ["Patch"], "url": "https://git.kernel.org/stable/c/09bce2138a30ef10d8821c8c3f73a4ab7a5726bc"}, {"source": "416baaa9-dc9f-4396-8d5f-8c081fb06d67", "tags": ["Patch"], "url": "https://git.kernel.org/stable/c/0a4eec84d4d2c4085d4ed8630fd74e4b39033c1b"}, {"source": "416baaa9-dc9f-4396-8d5f-8c081fb06d67", "tags": ["Patch"], "url": "https://git.kernel.org/stable/c/2baaf5bbab2ac474c4f92c10fcb3310f824db995"}, {"source": "416baaa9-dc9f-4396-8d5f-8c081fb06d67", "tags": ["Patch"], "url": "https://git.kernel.org/stable/c/4256a483fe58af66a46cbf3dc48ff26e580d3308"}, {"source": "416baaa9-dc9f-4396-8d5f-8c081fb06d67", "tags": ["Patch"], "url": "https://git.kernel.org/stable/c/705c79101ccf9edea5a00d761491a03ced314210"}, {"source": "416baaa9-dc9f-4396-8d5f-8c081fb06d67", "tags": ["Patch"], "url": "https://git.kernel.org/stable/c/da11bd4b697b393a207f19a2ed7d382a811a3ddc"}, {"source": "af854a3a-2127-422b-91ae-364da2661108", "tags": ["Mailing List", "Third Party Advisory"], "url": "https://lists.debian.org/debian-lts-announce/2025/10/msg00008.html"}], "sourceIdentifier": "416baaa9-dc9f-4396-8d5f-8c081fb06d67", "vulnStatus": "Modified", "weaknesses": [{"description": [{"lang": "en", "value": "CWE-416"}], "source": "nvd@nist.gov", "type": "Primary"}]}

{"bugzilla": {"description": "kernel: smb: client: fix use-after-free in cifs_oplock_break", "id": "2388928", "url": "https://bugzilla.redhat.com/show_bug.cgi?id=2388928"}, "csaw": false, "cvss3": {"cvss3_base_score": "5.5", "cvss3_scoring_vector": "CVSS:3.1/AV:L/AC:L/PR:L/UI:N/S:U/C:N/I:N/A:H", "status": "draft"}, "details": ["In the Linux kernel, the following vulnerability has been resolved:\nsmb: client: fix use-after-free in cifs_oplock_break\nA race condition can occur in cifs_oplock_break() leading to a\nuse-after-free of the cinode structure when unmounting:\ncifs_oplock_break()\n_cifsFileInfo_put(cfile)\ncifsFileInfo_put_final()\ncifs_sb_deactive()\n[last ref, start releasing sb]\nkill_sb()\nkill_anon_super()\ngeneric_shutdown_super()\nevict_inodes()\ndispose_list()\nevict()\ndestroy_inode()\ncall_rcu(&inode->i_rcu, i_callback)\nspin_lock(&cinode->open_file_lock) <- OK\n[later] i_callback()\ncifs_free_inode()\nkmem_cache_free(cinode)\nspin_unlock(&cinode->open_file_lock) <- UAF\ncifs_done_oplock_break(cinode) <- UAF\nThe issue occurs when umount has already released its reference to the\nsuperblock. When _cifsFileInfo_put() calls cifs_sb_deactive(), this\nreleases the last reference, triggering the immediate cleanup of all\ninodes under RCU. However, cifs_oplock_break() continues to access the\ncinode after this point, resulting in use-after-free.\nFix this by holding an extra reference to the superblock during the\nentire oplock break operation. This ensures that the superblock and\nits inodes remain valid until the oplock break completes."], "name": "CVE-2025-38527", "package_state": [{"cpe": "cpe:/o:redhat:enterprise_linux:10", "fix_state": "Fix deferred", "package_name": "kernel", "product_name": "Red Hat Enterprise Linux 10"}, {"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:8", "fix_state": "Fix deferred", "package_name": "kernel", "product_name": "Red Hat Enterprise Linux 8"}, {"cpe": "cpe:/o:redhat:enterprise_linux:8", "fix_state": "Fix deferred", "package_name": "kernel-rt", "product_name": "Red Hat Enterprise Linux 8"}, {"cpe": "cpe:/o:redhat:enterprise_linux:9", "fix_state": "Fix deferred", "package_name": "kernel", "product_name": "Red Hat Enterprise Linux 9"}, {"cpe": "cpe:/o:redhat:enterprise_linux:9", "fix_state": "Fix deferred", "package_name": "kernel-rt", "product_name": "Red Hat Enterprise Linux 9"}], "public_date": "2025-08-16T00:00:00Z", "references": ["https://www.cve.org/CVERecord?id=CVE-2025-38527\nhttps://nvd.nist.gov/vuln/detail/CVE-2025-38527\nhttps://lore.kernel.org/linux-cve-announce/2025081654-CVE-2025-38527-c389@gregkh/T"], "threat_severity": "Moderate"}

{"created": "2025-08-18T20:50:07.356904+00:00", "updated": "2025-08-18T20:50:07.356980+00:00", "vendors": ["linux", "linux$PRODUCT$linux_kernel"]}