CVE-2025-21884

{"dataType": "CVE_RECORD", "dataVersion": "5.2", "cveMetadata": {"cveId": "CVE-2025-21884", "assignerOrgId": "416baaa9-dc9f-4396-8d5f-8c081fb06d67", "state": "PUBLISHED", "assignerShortName": "Linux", "dateReserved": "2024-12-29T08:45:45.782Z", "datePublished": "2025-03-27T14:57:12.486Z", "dateUpdated": "2026-10-15T21:51:54.699Z"}, "containers": {"cna": {"providerMetadata": {"orgId": "416baaa9-dc9f-4396-8d5f-8c081fb06d67", "shortName": "Linux", "dateUpdated": "2026-08-05T11:55:06.894Z"}, "descriptions": [{"lang": "en", "value": "In the Linux kernel, the following vulnerability has been resolved:\n\nnet: better track kernel sockets lifetime\n\nWhile kernel sockets are dismantled during pernet_operations->exit(),\ntheir freeing can be delayed by any tx packets still held in qdisc\nor device queues, due to skb_set_owner_w() prior calls.\n\nThis then trigger the following warning from ref_tracker_dir_exit() [1]\n\nTo fix this, make sure that kernel sockets own a reference on net->passive.\n\nAdd sk_net_refcnt_upgrade() helper, used whenever a kernel socket\nis converted to a refcounted one.\n\n[1]\n\n[ 136.263918][ T35] ref_tracker: net notrefcnt@ffff8880638f01e0 has 1/2 users at\n[ 136.263918][ T35] sk_alloc+0x2b3/0x370\n[ 136.263918][ T35] inet6_create+0x6ce/0x10f0\n[ 136.263918][ T35] __sock_create+0x4c0/0xa30\n[ 136.263918][ T35] inet_ctl_sock_create+0xc2/0x250\n[ 136.263918][ T35] igmp6_net_init+0x39/0x390\n[ 136.263918][ T35] ops_init+0x31e/0x590\n[ 136.263918][ T35] setup_net+0x287/0x9e0\n[ 136.263918][ T35] copy_net_ns+0x33f/0x570\n[ 136.263918][ T35] create_new_namespaces+0x425/0x7b0\n[ 136.263918][ T35] unshare_nsproxy_namespaces+0x124/0x180\n[ 136.263918][ T35] ksys_unshare+0x57d/0xa70\n[ 136.263918][ T35] __x64_sys_unshare+0x38/0x40\n[ 136.263918][ T35] do_syscall_64+0xf3/0x230\n[ 136.263918][ T35] entry_SYSCALL_64_after_hwframe+0x77/0x7f\n[ 136.263918][ T35]\n[ 136.343488][ T35] ref_tracker: net notrefcnt@ffff8880638f01e0 has 1/2 users at\n[ 136.343488][ T35] sk_alloc+0x2b3/0x370\n[ 136.343488][ T35] inet6_create+0x6ce/0x10f0\n[ 136.343488][ T35] __sock_create+0x4c0/0xa30\n[ 136.343488][ T35] inet_ctl_sock_create+0xc2/0x250\n[ 136.343488][ T35] ndisc_net_init+0xa7/0x2b0\n[ 136.343488][ T35] ops_init+0x31e/0x590\n[ 136.343488][ T35] setup_net+0x287/0x9e0\n[ 136.343488][ T35] copy_net_ns+0x33f/0x570\n[ 136.343488][ T35] create_new_namespaces+0x425/0x7b0\n[ 136.343488][ T35] unshare_nsproxy_namespaces+0x124/0x180\n[ 136.343488][ T35] ksys_unshare+0x57d/0xa70\n[ 136.343488][ T35] __x64_sys_unshare+0x38/0x40\n[ 136.343488][ T35] do_syscall_64+0xf3/0x230\n[ 136.343488][ T35] entry_SYSCALL_64_after_hwframe+0x77/0x7f"}], "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": "AV:L - The bug is triggered entirely through local syscalls \u2014 `unshare(CLONE_NEWUSER|CLONE_NEWNET)` to create the netns, netlink/rtnetlink to add a device and a delaying qdisc, then namespace exit to run `cleanup_net()`; the syzbot traces show the path rooted at `__x64_sys_unshare`. No remote peer input is required or sufficient to reach it.\nAC:L - The attacker controls both halves of the window: they configure the device/qdisc that holds the kernel socket's TX skb (e.g. netem delay) and they choose exactly when to destroy the namespace, so the socket reliably outlives `net_passive_dec()`; the syzkaller reproducer hit it repeatably. Namespace churn also lets the attacker groom the freed `net_cachep` object before the deferred `__sk_destruct()` runs.\nPR:L - An unprivileged local account can create the network namespace and its per-netns kernel sockets via unprivileged user namespaces (`unshare -Urn`), which is enabled by default on mainstream distributions and Android. CAP_NET_ADMIN inside the new netns \u2014 granted automatically \u2014 is enough to add the device and qdisc needed to delay the kernel socket's skbs.\nUI:N - The attacking process performs every step itself: create the namespace, configure the delaying queue, trigger MLD/NDISC transmission, and exit. No victim action or cooperating process is needed.\nS:U - The freed `struct net`/`net->gen` slab objects and the sockets that dereference them all live in the kernel's own security authority. No hypervisor, IOMMU, or sandbox boundary is crossed, so this is standard in-kernel corruption.\nC:H - The kernel socket retains a completely unreferenced `struct net *`, so after `net_passive_dec()` frees `net->gen` and returns the `struct net` to `net_cachep`, subsequent `sock_net(sk)` dereferences read reallocated slab contents \u2014 the same class of defect that produced a KASAN slab-use-after-free read in the companion commit `65161fb544aa`. A use-after-free on a long-lived, attacker-groomable object yields an information-disclosure primitive.\nI:H - `__sk_destruct()` performs `__netns_tracker_free(sock_net(sk), &sk->ns_tracker, false)` on the dangling pointer, driving `ref_tracker_free()`'s list unlink and counter updates into the freed-and-reallocated `struct net`, which is a write into attacker-groomed memory. Reallocating the freed slot with a fresh namespace also lets the stale socket operate on the wrong `struct net`, corrupting per-netns state and enabling escalation to control-flow hijack.\nA:H - Use-after-free of `struct net` and its freed `net->gen` array produces oopses and panics even when not weaponized, and the pre-fix condition additionally trips `ref_tracker_dir_exit()`'s WARN with `CONFIG_NET_NS_REFCNT_TRACKER=y` (fatal under `panic_on_warn`). The sequence can be repeated in a loop by an unprivileged user until the box crashes."}]}], "affected": [{"product": "Linux", "vendor": "Linux", "defaultStatus": "unaffected", "repo": "https://git.kernel.org/pub/scm/linux/kernel/git/stable/linux.git", "programFiles": ["include/net/sock.h", "net/core/sock.c", "net/mptcp/subflow.c", "net/netlink/af_netlink.c", "net/rds/tcp.c", "net/smc/af_smc.c", "net/sunrpc/svcsock.c", "net/sunrpc/xprtsock.c"], "versions": [{"version": "0cafd77dcd032d1687efaba5598cf07bce85997f", "lessThan": "2668e038800b946d269f96ec1b258c01930a242c", "status": "affected", "versionType": "git"}, {"version": "0cafd77dcd032d1687efaba5598cf07bce85997f", "lessThan": "4ceb0bd4ffd009821b585ce6a8033b12b59fb5fb", "status": "affected", "versionType": "git"}, {"version": "0cafd77dcd032d1687efaba5598cf07bce85997f", "lessThan": "c31a732fac46b00b95b78fcc9c37cb48dd6f2e0c", "status": "affected", "versionType": "git"}, {"version": "0cafd77dcd032d1687efaba5598cf07bce85997f", "lessThan": "5c70eb5c593d64d93b178905da215a9fd288a4b5", "status": "affected", "versionType": "git"}]}, {"product": "Linux", "vendor": "Linux", "defaultStatus": "affected", "repo": "https://git.kernel.org/pub/scm/linux/kernel/git/stable/linux.git", "programFiles": ["include/net/sock.h", "net/core/sock.c", "net/mptcp/subflow.c", "net/netlink/af_netlink.c", "net/rds/tcp.c", "net/smc/af_smc.c", "net/sunrpc/svcsock.c", "net/sunrpc/xprtsock.c"], "versions": [{"version": "6.2", "status": "affected"}, {"version": "0", "lessThan": "6.2", "status": "unaffected", "versionType": "semver"}, {"version": "6.6.103", "lessThanOrEqual": "6.6.*", "status": "unaffected", "versionType": "semver"}, {"version": "6.12.43", "lessThanOrEqual": "6.12.*", "status": "unaffected", "versionType": "semver"}, {"version": "6.13.6", "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": "6.2", "versionEndExcluding": "6.6.103"}, {"vulnerable": true, "criteria": "cpe:2.3:o:linux:linux_kernel:*:*:*:*:*:*:*:*", "versionStartIncluding": "6.2", "versionEndExcluding": "6.12.43"}, {"vulnerable": true, "criteria": "cpe:2.3:o:linux:linux_kernel:*:*:*:*:*:*:*:*", "versionStartIncluding": "6.2", "versionEndExcluding": "6.13.6"}, {"vulnerable": true, "criteria": "cpe:2.3:o:linux:linux_kernel:*:*:*:*:*:*:*:*", "versionStartIncluding": "6.2", "versionEndExcluding": "6.14"}]}]}], "references": [{"url": "https://git.kernel.org/stable/c/2668e038800b946d269f96ec1b258c01930a242c"}, {"url": "https://git.kernel.org/stable/c/4ceb0bd4ffd009821b585ce6a8033b12b59fb5fb"}, {"url": "https://git.kernel.org/stable/c/c31a732fac46b00b95b78fcc9c37cb48dd6f2e0c"}, {"url": "https://git.kernel.org/stable/c/5c70eb5c593d64d93b178905da215a9fd288a4b5"}], "title": "net: better track kernel sockets lifetime", "x_generator": {"engine": "bippy-1.2.0"}}, "adp": [{"metrics": [{"other": {"type": "ssvc", "content": {"id": "CVE-2025-21884", "role": "CISA Coordinator", "options": [{"Exploitation": "none"}, {"Automatable": "no"}, {"Technical Impact": "total"}], "version": "2.0.3", "timestamp": "2026-10-15T21:43:27.839000Z"}}}], "title": "CISA ADP Vulnrichment", "providerMetadata": {"orgId": "134c704f-9b21-4f2e-91b3-4a467353bcc0", "shortName": "CISA-ADP", "dateUpdated": "2026-10-15T21:51:54.699Z"}}]}}

{"dataType": "CVE_RECORD", "containers": {"adp": [{"title": "CISA ADP Vulnrichment", "metrics": [{"other": {"type": "ssvc", "content": {"id": "CVE-2025-21884", "role": "CISA Coordinator", "options": [{"Exploitation": "none"}, {"Automatable": "no"}, {"Technical Impact": "total"}], "version": "2.0.3", "timestamp": "2026-10-15T21:43:27.839000Z"}}}], "providerMetadata": {"orgId": "134c704f-9b21-4f2e-91b3-4a467353bcc0", "shortName": "CISA-ADP", "dateUpdated": "2026-10-15T21:43:28.611Z"}}], "cna": {"title": "net: better track kernel sockets lifetime", "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": "AV:L - The bug is triggered entirely through local syscalls \u2014 `unshare(CLONE_NEWUSER|CLONE_NEWNET)` to create the netns, netlink/rtnetlink to add a device and a delaying qdisc, then namespace exit to run `cleanup_net()`; the syzbot traces show the path rooted at `__x64_sys_unshare`. No remote peer input is required or sufficient to reach it.\nAC:L - The attacker controls both halves of the window: they configure the device/qdisc that holds the kernel socket's TX skb (e.g. netem delay) and they choose exactly when to destroy the namespace, so the socket reliably outlives `net_passive_dec()`; the syzkaller reproducer hit it repeatably. Namespace churn also lets the attacker groom the freed `net_cachep` object before the deferred `__sk_destruct()` runs.\nPR:L - An unprivileged local account can create the network namespace and its per-netns kernel sockets via unprivileged user namespaces (`unshare -Urn`), which is enabled by default on mainstream distributions and Android. CAP_NET_ADMIN inside the new netns \u2014 granted automatically \u2014 is enough to add the device and qdisc needed to delay the kernel socket's skbs.\nUI:N - The attacking process performs every step itself: create the namespace, configure the delaying queue, trigger MLD/NDISC transmission, and exit. No victim action or cooperating process is needed.\nS:U - The freed `struct net`/`net->gen` slab objects and the sockets that dereference them all live in the kernel's own security authority. No hypervisor, IOMMU, or sandbox boundary is crossed, so this is standard in-kernel corruption.\nC:H - The kernel socket retains a completely unreferenced `struct net *`, so after `net_passive_dec()` frees `net->gen` and returns the `struct net` to `net_cachep`, subsequent `sock_net(sk)` dereferences read reallocated slab contents \u2014 the same class of defect that produced a KASAN slab-use-after-free read in the companion commit `65161fb544aa`. A use-after-free on a long-lived, attacker-groomable object yields an information-disclosure primitive.\nI:H - `__sk_destruct()` performs `__netns_tracker_free(sock_net(sk), &sk->ns_tracker, false)` on the dangling pointer, driving `ref_tracker_free()`'s list unlink and counter updates into the freed-and-reallocated `struct net`, which is a write into attacker-groomed memory. Reallocating the freed slot with a fresh namespace also lets the stale socket operate on the wrong `struct net`, corrupting per-netns state and enabling escalation to control-flow hijack.\nA:H - Use-after-free of `struct net` and its freed `net->gen` array produces oopses and panics even when not weaponized, and the pre-fix condition additionally trips `ref_tracker_dir_exit()`'s WARN with `CONFIG_NET_NS_REFCNT_TRACKER=y` (fatal under `panic_on_warn`). The sequence can be repeated in a loop by an unprivileged user until the box crashes."}]}], "affected": [{"repo": "https://git.kernel.org/pub/scm/linux/kernel/git/stable/linux.git", "vendor": "Linux", "product": "Linux", "versions": [{"status": "affected", "version": "0cafd77dcd032d1687efaba5598cf07bce85997f", "lessThan": "2668e038800b946d269f96ec1b258c01930a242c", "versionType": "git"}, {"status": "affected", "version": "0cafd77dcd032d1687efaba5598cf07bce85997f", "lessThan": "4ceb0bd4ffd009821b585ce6a8033b12b59fb5fb", "versionType": "git"}, {"status": "affected", "version": "0cafd77dcd032d1687efaba5598cf07bce85997f", "lessThan": "c31a732fac46b00b95b78fcc9c37cb48dd6f2e0c", "versionType": "git"}, {"status": "affected", "version": "0cafd77dcd032d1687efaba5598cf07bce85997f", "lessThan": "5c70eb5c593d64d93b178905da215a9fd288a4b5", "versionType": "git"}], "programFiles": ["include/net/sock.h", "net/core/sock.c", "net/mptcp/subflow.c", "net/netlink/af_netlink.c", "net/rds/tcp.c", "net/smc/af_smc.c", "net/sunrpc/svcsock.c", "net/sunrpc/xprtsock.c"], "defaultStatus": "unaffected"}, {"repo": "https://git.kernel.org/pub/scm/linux/kernel/git/stable/linux.git", "vendor": "Linux", "product": "Linux", "versions": [{"status": "affected", "version": "6.2"}, {"status": "unaffected", "version": "0", "lessThan": "6.2", "versionType": "semver"}, {"status": "unaffected", "version": "6.6.103", "versionType": "semver", "lessThanOrEqual": "6.6.*"}, {"status": "unaffected", "version": "6.12.43", "versionType": "semver", "lessThanOrEqual": "6.12.*"}, {"status": "unaffected", "version": "6.13.6", "versionType": "semver", "lessThanOrEqual": "6.13.*"}, {"status": "unaffected", "version": "6.14", "versionType": "original_commit_for_fix", "lessThanOrEqual": "*"}], "programFiles": ["include/net/sock.h", "net/core/sock.c", "net/mptcp/subflow.c", "net/netlink/af_netlink.c", "net/rds/tcp.c", "net/smc/af_smc.c", "net/sunrpc/svcsock.c", "net/sunrpc/xprtsock.c"], "defaultStatus": "affected"}], "references": [{"url": "https://git.kernel.org/stable/c/2668e038800b946d269f96ec1b258c01930a242c"}, {"url": "https://git.kernel.org/stable/c/4ceb0bd4ffd009821b585ce6a8033b12b59fb5fb"}, {"url": "https://git.kernel.org/stable/c/c31a732fac46b00b95b78fcc9c37cb48dd6f2e0c"}, {"url": "https://git.kernel.org/stable/c/5c70eb5c593d64d93b178905da215a9fd288a4b5"}], "x_generator": {"engine": "bippy-1.2.0"}, "descriptions": [{"lang": "en", "value": "In the Linux kernel, the following vulnerability has been resolved:\n\nnet: better track kernel sockets lifetime\n\nWhile kernel sockets are dismantled during pernet_operations->exit(),\ntheir freeing can be delayed by any tx packets still held in qdisc\nor device queues, due to skb_set_owner_w() prior calls.\n\nThis then trigger the following warning from ref_tracker_dir_exit() [1]\n\nTo fix this, make sure that kernel sockets own a reference on net->passive.\n\nAdd sk_net_refcnt_upgrade() helper, used whenever a kernel socket\nis converted to a refcounted one.\n\n[1]\n\n[ 136.263918][ T35] ref_tracker: net notrefcnt@ffff8880638f01e0 has 1/2 users at\n[ 136.263918][ T35] sk_alloc+0x2b3/0x370\n[ 136.263918][ T35] inet6_create+0x6ce/0x10f0\n[ 136.263918][ T35] __sock_create+0x4c0/0xa30\n[ 136.263918][ T35] inet_ctl_sock_create+0xc2/0x250\n[ 136.263918][ T35] igmp6_net_init+0x39/0x390\n[ 136.263918][ T35] ops_init+0x31e/0x590\n[ 136.263918][ T35] setup_net+0x287/0x9e0\n[ 136.263918][ T35] copy_net_ns+0x33f/0x570\n[ 136.263918][ T35] create_new_namespaces+0x425/0x7b0\n[ 136.263918][ T35] unshare_nsproxy_namespaces+0x124/0x180\n[ 136.263918][ T35] ksys_unshare+0x57d/0xa70\n[ 136.263918][ T35] __x64_sys_unshare+0x38/0x40\n[ 136.263918][ T35] do_syscall_64+0xf3/0x230\n[ 136.263918][ T35] entry_SYSCALL_64_after_hwframe+0x77/0x7f\n[ 136.263918][ T35]\n[ 136.343488][ T35] ref_tracker: net notrefcnt@ffff8880638f01e0 has 1/2 users at\n[ 136.343488][ T35] sk_alloc+0x2b3/0x370\n[ 136.343488][ T35] inet6_create+0x6ce/0x10f0\n[ 136.343488][ T35] __sock_create+0x4c0/0xa30\n[ 136.343488][ T35] inet_ctl_sock_create+0xc2/0x250\n[ 136.343488][ T35] ndisc_net_init+0xa7/0x2b0\n[ 136.343488][ T35] ops_init+0x31e/0x590\n[ 136.343488][ T35] setup_net+0x287/0x9e0\n[ 136.343488][ T35] copy_net_ns+0x33f/0x570\n[ 136.343488][ T35] create_new_namespaces+0x425/0x7b0\n[ 136.343488][ T35] unshare_nsproxy_namespaces+0x124/0x180\n[ 136.343488][ T35] ksys_unshare+0x57d/0xa70\n[ 136.343488][ T35] __x64_sys_unshare+0x38/0x40\n[ 136.343488][ T35] do_syscall_64+0xf3/0x230\n[ 136.343488][ T35] entry_SYSCALL_64_after_hwframe+0x77/0x7f"}], "cpeApplicability": [{"nodes": [{"negate": false, "cpeMatch": [{"criteria": "cpe:2.3:o:linux:linux_kernel:*:*:*:*:*:*:*:*", "vulnerable": true, "versionEndExcluding": "6.6.103", "versionStartIncluding": "6.2"}, {"criteria": "cpe:2.3:o:linux:linux_kernel:*:*:*:*:*:*:*:*", "vulnerable": true, "versionEndExcluding": "6.12.43", "versionStartIncluding": "6.2"}, {"criteria": "cpe:2.3:o:linux:linux_kernel:*:*:*:*:*:*:*:*", "vulnerable": true, "versionEndExcluding": "6.13.6", "versionStartIncluding": "6.2"}, {"criteria": "cpe:2.3:o:linux:linux_kernel:*:*:*:*:*:*:*:*", "vulnerable": true, "versionEndExcluding": "6.14", "versionStartIncluding": "6.2"}], "operator": "OR"}]}], "providerMetadata": {"orgId": "416baaa9-dc9f-4396-8d5f-8c081fb06d67", "shortName": "Linux", "dateUpdated": "2026-08-05T11:55:06.894Z"}}}, "cveMetadata": {"cveId": "CVE-2025-21884", "state": "PUBLISHED", "dateUpdated": "2026-10-15T21:51:54.699Z", "dateReserved": "2024-12-29T08:45:45.782Z", "assignerOrgId": "416baaa9-dc9f-4396-8d5f-8c081fb06d67", "datePublished": "2025-03-27T14:57:12.486Z", "assignerShortName": "Linux"}, "dataVersion": "5.2"}

{"affected": [{"affectedData": [{"defaultStatus": "unaffected", "product": "Linux", "programFiles": ["include/net/sock.h", "net/core/sock.c", "net/mptcp/subflow.c", "net/netlink/af_netlink.c", "net/rds/tcp.c", "net/smc/af_smc.c", "net/sunrpc/svcsock.c", "net/sunrpc/xprtsock.c"], "repo": "https://git.kernel.org/pub/scm/linux/kernel/git/stable/linux.git", "vendor": "Linux", "versions": [{"lessThan": "2668e038800b946d269f96ec1b258c01930a242c", "status": "affected", "version": "0cafd77dcd032d1687efaba5598cf07bce85997f", "versionType": "git"}, {"lessThan": "4ceb0bd4ffd009821b585ce6a8033b12b59fb5fb", "status": "affected", "version": "0cafd77dcd032d1687efaba5598cf07bce85997f", "versionType": "git"}, {"lessThan": "c31a732fac46b00b95b78fcc9c37cb48dd6f2e0c", "status": "affected", "version": "0cafd77dcd032d1687efaba5598cf07bce85997f", "versionType": "git"}, {"lessThan": "5c70eb5c593d64d93b178905da215a9fd288a4b5", "status": "affected", "version": "0cafd77dcd032d1687efaba5598cf07bce85997f", "versionType": "git"}]}, {"defaultStatus": "affected", "product": "Linux", "programFiles": ["include/net/sock.h", "net/core/sock.c", "net/mptcp/subflow.c", "net/netlink/af_netlink.c", "net/rds/tcp.c", "net/smc/af_smc.c", "net/sunrpc/svcsock.c", "net/sunrpc/xprtsock.c"], "repo": "https://git.kernel.org/pub/scm/linux/kernel/git/stable/linux.git", "vendor": "Linux", "versions": [{"status": "affected", "version": "6.2"}, {"lessThan": "6.2", "status": "unaffected", "version": "0", "versionType": "semver"}, {"lessThanOrEqual": "6.6.*", "status": "unaffected", "version": "6.6.103", "versionType": "semver"}, {"lessThanOrEqual": "6.12.*", "status": "unaffected", "version": "6.12.43", "versionType": "semver"}, {"lessThanOrEqual": "6.13.*", "status": "unaffected", "version": "6.13.6", "versionType": "semver"}, {"lessThanOrEqual": "*", "status": "unaffected", "version": "6.14", "versionType": "original_commit_for_fix"}]}], "source": "416baaa9-dc9f-4396-8d5f-8c081fb06d67"}], "configurations": [{"nodes": [{"cpeMatch": [{"criteria": "cpe:2.3:o:linux:linux_kernel:*:*:*:*:*:*:*:*", "matchCriteriaId": "F2293654-7169-49B5-8D0D-EE51EF8B8E48", "versionEndExcluding": "6.6.103", "versionStartIncluding": "6.2", "vulnerable": true}, {"criteria": "cpe:2.3:o:linux:linux_kernel:*:*:*:*:*:*:*:*", "matchCriteriaId": "472C5F87-2BF3-4FAB-9B21-DA7513977363", "versionEndExcluding": "6.12.43", "versionStartIncluding": "6.7", "vulnerable": true}, {"criteria": "cpe:2.3:o:linux:linux_kernel:*:*:*:*:*:*:*:*", "matchCriteriaId": "64F12D9B-71C2-4CD7-A288-0D5EF1709620", "versionEndExcluding": "6.13.6", "versionStartIncluding": "6.13", "vulnerable": true}, {"criteria": "cpe:2.3:o:linux:linux_kernel:6.14:rc1:*:*:*:*:*:*", "matchCriteriaId": "186716B6-2B66-4BD0-852E-D48E71C0C85F", "vulnerable": true}, {"criteria": "cpe:2.3:o:linux:linux_kernel:6.14:rc2:*:*:*:*:*:*", "matchCriteriaId": "0D3E781C-403A-498F-9DA9-ECEE50F41E75", "vulnerable": true}, {"criteria": "cpe:2.3:o:linux:linux_kernel:6.14:rc3:*:*:*:*:*:*", "matchCriteriaId": "66619FB8-0AAF-4166-B2CF-67B24143261D", "vulnerable": true}, {"criteria": "cpe:2.3:o:linux:linux_kernel:6.14:rc4:*:*:*:*:*:*", "matchCriteriaId": "D3D6550E-6679-4560-902D-AF52DCFE905B", "vulnerable": true}], "negate": false, "operator": "OR"}]}], "cveTags": [], "descriptions": [{"lang": "en", "value": "In the Linux kernel, the following vulnerability has been resolved:\n\nnet: better track kernel sockets lifetime\n\nWhile kernel sockets are dismantled during pernet_operations->exit(),\ntheir freeing can be delayed by any tx packets still held in qdisc\nor device queues, due to skb_set_owner_w() prior calls.\n\nThis then trigger the following warning from ref_tracker_dir_exit() [1]\n\nTo fix this, make sure that kernel sockets own a reference on net->passive.\n\nAdd sk_net_refcnt_upgrade() helper, used whenever a kernel socket\nis converted to a refcounted one.\n\n[1]\n\n[ 136.263918][ T35] ref_tracker: net notrefcnt@ffff8880638f01e0 has 1/2 users at\n[ 136.263918][ T35] sk_alloc+0x2b3/0x370\n[ 136.263918][ T35] inet6_create+0x6ce/0x10f0\n[ 136.263918][ T35] __sock_create+0x4c0/0xa30\n[ 136.263918][ T35] inet_ctl_sock_create+0xc2/0x250\n[ 136.263918][ T35] igmp6_net_init+0x39/0x390\n[ 136.263918][ T35] ops_init+0x31e/0x590\n[ 136.263918][ T35] setup_net+0x287/0x9e0\n[ 136.263918][ T35] copy_net_ns+0x33f/0x570\n[ 136.263918][ T35] create_new_namespaces+0x425/0x7b0\n[ 136.263918][ T35] unshare_nsproxy_namespaces+0x124/0x180\n[ 136.263918][ T35] ksys_unshare+0x57d/0xa70\n[ 136.263918][ T35] __x64_sys_unshare+0x38/0x40\n[ 136.263918][ T35] do_syscall_64+0xf3/0x230\n[ 136.263918][ T35] entry_SYSCALL_64_after_hwframe+0x77/0x7f\n[ 136.263918][ T35]\n[ 136.343488][ T35] ref_tracker: net notrefcnt@ffff8880638f01e0 has 1/2 users at\n[ 136.343488][ T35] sk_alloc+0x2b3/0x370\n[ 136.343488][ T35] inet6_create+0x6ce/0x10f0\n[ 136.343488][ T35] __sock_create+0x4c0/0xa30\n[ 136.343488][ T35] inet_ctl_sock_create+0xc2/0x250\n[ 136.343488][ T35] ndisc_net_init+0xa7/0x2b0\n[ 136.343488][ T35] ops_init+0x31e/0x590\n[ 136.343488][ T35] setup_net+0x287/0x9e0\n[ 136.343488][ T35] copy_net_ns+0x33f/0x570\n[ 136.343488][ T35] create_new_namespaces+0x425/0x7b0\n[ 136.343488][ T35] unshare_nsproxy_namespaces+0x124/0x180\n[ 136.343488][ T35] ksys_unshare+0x57d/0xa70\n[ 136.343488][ T35] __x64_sys_unshare+0x38/0x40\n[ 136.343488][ T35] do_syscall_64+0xf3/0x230\n[ 136.343488][ T35] entry_SYSCALL_64_after_hwframe+0x77/0x7f"}, {"lang": "es", "value": "En el kernel de Linux, se ha resuelto la siguiente vulnerabilidad: net: mejorar el seguimiento del ciclo de vida de los sockets del kernel. Mientras los sockets del kernel se desmantelan durante pernet_operations->exit(), su liberaci\u00f3n puede verse retrasada por cualquier paquete de transmisi\u00f3n que a\u00fan se encuentre en la qdisc o en las colas de dispositivos, debido a llamadas previas a skb_set_owner_w(). Esto genera la siguiente advertencia de ref_tracker_dir_exit() [1]. Para solucionar esto, aseg\u00farese de que los sockets del kernel posean una referencia en net->passive. Agregue el asistente sk_net_refcnt_upgrade(), que se utiliza siempre que un socket del kernel se convierte a uno con recuento de referencia. [1] [ 136.263918][ T35] ref_tracker: net notrefcnt@ffff8880638f01e0 has 1/2 users at [ 136.263918][ T35] sk_alloc+0x2b3/0x370 [ 136.263918][ T35] inet6_create+0x6ce/0x10f0 [ 136.263918][ T35] __sock_create+0x4c0/0xa30 [ 136.263918][ T35] inet_ctl_sock_create+0xc2/0x250 [ 136.263918][ T35] igmp6_net_init+0x39/0x390 [ 136.263918][ T35] ops_init+0x31e/0x590 [ 136.263918][ T35] setup_net+0x287/0x9e0 [ 136.263918][ T35] copy_net_ns+0x33f/0x570 [ 136.263918][ T35] create_new_namespaces+0x425/0x7b0 [ 136.263918][ T35] unshare_nsproxy_namespaces+0x124/0x180 [ 136.263918][ T35] ksys_unshare+0x57d/0xa70 [ 136.263918][ T35] __x64_sys_unshare+0x38/0x40 [ 136.263918][ T35] do_syscall_64+0xf3/0x230 [ 136.263918][ T35] entry_SYSCALL_64_after_hwframe+0x77/0x7f [ 136.263918][ T35] [ 136.343488][ T35] ref_tracker: net notrefcnt@ffff8880638f01e0 has 1/2 users at [ 136.343488][ T35] sk_alloc+0x2b3/0x370 [ 136.343488][ T35] inet6_create+0x6ce/0x10f0 [ 136.343488][ T35] __sock_create+0x4c0/0xa30 [ 136.343488][ T35] inet_ctl_sock_create+0xc2/0x250 [ 136.343488][ T35] ndisc_net_init+0xa7/0x2b0 [ 136.343488][ T35] ops_init+0x31e/0x590 [ 136.343488][ T35] setup_net+0x287/0x9e0 [ 136.343488][ T35] copy_net_ns+0x33f/0x570 [ 136.343488][ T35] create_new_namespaces+0x425/0x7b0 [ 136.343488][ T35] unshare_nsproxy_namespaces+0x124/0x180 [ 136.343488][ T35] ksys_unshare+0x57d/0xa70 [ 136.343488][ T35] __x64_sys_unshare+0x38/0x40 [ 136.343488][ T35] do_syscall_64+0xf3/0x230 [ 136.343488][ T35] entry_SYSCALL_64_after_hwframe+0x77/0x7f"}], "id": "CVE-2025-21884", "lastModified": "2026-10-15T22:18:10.910", "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": 5.5, "baseSeverity": "MEDIUM", "confidentialityImpact": "NONE", "integrityImpact": "NONE", "privilegesRequired": "LOW", "scope": "UNCHANGED", "userInteraction": "NONE", "vectorString": "CVSS:3.1/AV:L/AC:L/PR:L/UI:N/S:U/C:N/I:N/A:H", "version": "3.1"}, "exploitabilityScore": 1.8, "impactScore": 3.6, "source": "nvd@nist.gov", "type": "Primary"}], "ssvcV203": [{"source": "134c704f-9b21-4f2e-91b3-4a467353bcc0", "ssvcData": {"id": "CVE-2025-21884", "options": [{"exploitation": "none"}, {"automatable": "no"}, {"technicalImpact": "total"}], "role": "CISA Coordinator", "timestamp": "2026-10-15T21:43:27.839000Z", "version": "2.0.3"}}]}, "published": "2025-03-27T15:15:56.313", "references": [{"source": "416baaa9-dc9f-4396-8d5f-8c081fb06d67", "tags": ["Patch"], "url": "https://git.kernel.org/stable/c/2668e038800b946d269f96ec1b258c01930a242c"}, {"source": "416baaa9-dc9f-4396-8d5f-8c081fb06d67", "tags": ["Patch"], "url": "https://git.kernel.org/stable/c/4ceb0bd4ffd009821b585ce6a8033b12b59fb5fb"}, {"source": "416baaa9-dc9f-4396-8d5f-8c081fb06d67", "tags": ["Patch"], "url": "https://git.kernel.org/stable/c/5c70eb5c593d64d93b178905da215a9fd288a4b5"}, {"source": "416baaa9-dc9f-4396-8d5f-8c081fb06d67", "tags": ["Patch"], "url": "https://git.kernel.org/stable/c/c31a732fac46b00b95b78fcc9c37cb48dd6f2e0c"}], "sourceIdentifier": "416baaa9-dc9f-4396-8d5f-8c081fb06d67", "vulnStatus": "Modified", "weaknesses": [{"description": [{"lang": "en", "value": "NVD-CWE-noinfo"}], "source": "nvd@nist.gov", "type": "Primary"}]}

{"bugzilla": {"description": "kernel: net: better track kernel sockets lifetime", "id": "2355399", "url": "https://bugzilla.redhat.com/show_bug.cgi?id=2355399"}, "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:\nnet: better track kernel sockets lifetime\nWhile kernel sockets are dismantled during pernet_operations->exit(),\ntheir freeing can be delayed by any tx packets still held in qdisc\nor device queues, due to skb_set_owner_w() prior calls.\nThis then trigger the following warning from ref_tracker_dir_exit() [1]\nTo fix this, make sure that kernel sockets own a reference on net->passive.\nAdd sk_net_refcnt_upgrade() helper, used whenever a kernel socket\nis converted to a refcounted one.\n[1]\n[ 136.263918][ T35] ref_tracker: net notrefcnt@ffff8880638f01e0 has 1/2 users at\n[ 136.263918][ T35] sk_alloc+0x2b3/0x370\n[ 136.263918][ T35] inet6_create+0x6ce/0x10f0\n[ 136.263918][ T35] __sock_create+0x4c0/0xa30\n[ 136.263918][ T35] inet_ctl_sock_create+0xc2/0x250\n[ 136.263918][ T35] igmp6_net_init+0x39/0x390\n[ 136.263918][ T35] ops_init+0x31e/0x590\n[ 136.263918][ T35] setup_net+0x287/0x9e0\n[ 136.263918][ T35] copy_net_ns+0x33f/0x570\n[ 136.263918][ T35] create_new_namespaces+0x425/0x7b0\n[ 136.263918][ T35] unshare_nsproxy_namespaces+0x124/0x180\n[ 136.263918][ T35] ksys_unshare+0x57d/0xa70\n[ 136.263918][ T35] __x64_sys_unshare+0x38/0x40\n[ 136.263918][ T35] do_syscall_64+0xf3/0x230\n[ 136.263918][ T35] entry_SYSCALL_64_after_hwframe+0x77/0x7f\n[ 136.263918][ T35]\n[ 136.343488][ T35] ref_tracker: net notrefcnt@ffff8880638f01e0 has 1/2 users at\n[ 136.343488][ T35] sk_alloc+0x2b3/0x370\n[ 136.343488][ T35] inet6_create+0x6ce/0x10f0\n[ 136.343488][ T35] __sock_create+0x4c0/0xa30\n[ 136.343488][ T35] inet_ctl_sock_create+0xc2/0x250\n[ 136.343488][ T35] ndisc_net_init+0xa7/0x2b0\n[ 136.343488][ T35] ops_init+0x31e/0x590\n[ 136.343488][ T35] setup_net+0x287/0x9e0\n[ 136.343488][ T35] copy_net_ns+0x33f/0x570\n[ 136.343488][ T35] create_new_namespaces+0x425/0x7b0\n[ 136.343488][ T35] unshare_nsproxy_namespaces+0x124/0x180\n[ 136.343488][ T35] ksys_unshare+0x57d/0xa70\n[ 136.343488][ T35] __x64_sys_unshare+0x38/0x40\n[ 136.343488][ T35] do_syscall_64+0xf3/0x230\n[ 136.343488][ T35] entry_SYSCALL_64_after_hwframe+0x77/0x7f"], "name": "CVE-2025-21884", "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": "Out of support scope", "package_name": "kernel", "product_name": "Red Hat Enterprise Linux 6"}, {"cpe": "cpe:/o:redhat:enterprise_linux:7", "fix_state": "Out of support scope", "package_name": "kernel", "product_name": "Red Hat Enterprise Linux 7"}, {"cpe": "cpe:/o:redhat:enterprise_linux:7", "fix_state": "Out of support scope", "package_name": "kernel-rt", "product_name": "Red Hat Enterprise Linux 7"}, {"cpe": "cpe:/o:redhat:enterprise_linux:8", "fix_state": "Not affected", "package_name": "kernel", "product_name": "Red Hat Enterprise Linux 8"}, {"cpe": "cpe:/o:redhat:enterprise_linux:8", "fix_state": "Not affected", "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": "2025-03-27T00:00:00Z", "references": ["https://www.cve.org/CVERecord?id=CVE-2025-21884\nhttps://nvd.nist.gov/vuln/detail/CVE-2025-21884\nhttps://lore.kernel.org/linux-cve-announce/2025032713-CVE-2025-21884-b70c@gregkh/T"], "threat_severity": "Low"}

{}