{ "dataType": "CVE_RECORD", "dataVersion": "5.2", "cveMetadata": { "cveId": "CVE-2026-31406", "assignerOrgId": "416baaa9-dc9f-4396-8d5f-8c081fb06d67", "state": "PUBLISHED", "assignerShortName": "Linux", "dateReserved": "2026-03-09T15:48:24.086Z", "datePublished": "2026-04-06T07:38:18.840Z", "dateUpdated": "2026-08-05T12:22:15.395Z" }, "containers": { "cna": { "providerMetadata": { "orgId": "416baaa9-dc9f-4396-8d5f-8c081fb06d67", "shortName": "Linux", "dateUpdated": "2026-08-05T12:22:15.395Z" }, "descriptions": [ { "lang": "en", "value": "In the Linux kernel, the following vulnerability has been resolved:\n\nxfrm: Fix work re-schedule after cancel in xfrm_nat_keepalive_net_fini()\n\nAfter cancel_delayed_work_sync() is called from\nxfrm_nat_keepalive_net_fini(), xfrm_state_fini() flushes remaining\nstates via __xfrm_state_delete(), which calls\nxfrm_nat_keepalive_state_updated() to re-schedule nat_keepalive_work.\n\nThe following is a simple race scenario:\n\n cpu0 cpu1\n\ncleanup_net() [Round 1]\n ops_undo_list()\n xfrm_net_exit()\n xfrm_nat_keepalive_net_fini()\n cancel_delayed_work_sync(nat_keepalive_work);\n xfrm_state_fini()\n xfrm_state_flush()\n xfrm_state_delete(x)\n __xfrm_state_delete(x)\n xfrm_nat_keepalive_state_updated(x)\n schedule_delayed_work(nat_keepalive_work);\n rcu_barrier();\n net_complete_free();\n net_passive_dec(net);\n llist_add(&net->defer_free_list, &defer_free_list);\n\ncleanup_net() [Round 2]\n rcu_barrier();\n net_complete_free()\n kmem_cache_free(net_cachep, net);\n nat_keepalive_work()\n // on freed net\n\nTo prevent this, cancel_delayed_work_sync() is replaced with\ndisable_delayed_work_sync()." } ], "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 vulnerable path is reached through local namespace lifecycle and NETLINK_XFRM state configuration, not by remote packet processing. An attacker can create an affected outbound ESP-in-UDP XFRM state locally and tear down the network namespace.\nAC:L - The attacker controls creation of the NAT keepalive state and repeated teardown of the network namespace; the work reschedule after cancel is a direct consequence of the cleanup ordering. Any scheduling race can be retried and influenced locally, so there are no hard external conditions.\nPR:L - XFRM netlink operations require CAP_NET_ADMIN in the target network namespace. This is reachable by an unprivileged local user through a user namespace plus network namespace where they hold CAP_NET_ADMIN.\nUI:N - No victim action is required after the attacker runs local code. The attacker can configure the state and trigger namespace cleanup directly.\nS:U - The vulnerability corrupts kernel memory within the same kernel security authority. It is a standard local kernel compromise scenario, not a VM or hardware boundary escape.\nC:H - This is a use-after-free of a network namespace embedded delayed_work object and subsequent XFRM/netns state access. Per kernel scoring guidance, UAFs are treated as enabling high confidentiality impact.\nI:H - The dangling work item can operate on freed and potentially reclaimed kernel memory, giving a plausible path to memory corruption and control-flow compromise. Per kernel scoring guidance, UAFs are treated as high integrity impact.\nA:H - At minimum, executing delayed work on a freed struct net can dereference freed XFRM state and namespace data, causing an oops or panic. Repeated local triggering can reliably deny service." } ] } ], "affected": [ { "product": "Linux", "vendor": "Linux", "defaultStatus": "unaffected", "repo": "https://git.kernel.org/pub/scm/linux/kernel/git/stable/linux.git", "programFiles": [ "net/xfrm/xfrm_nat_keepalive.c" ], "versions": [ { "version": "f531d13bdfe3f4f084aaa8acae2cb0f02295f5ae", "lessThan": "32d0f44c2f14d60fe8e920e69a28c11051543ec1", "status": "affected", "versionType": "git" }, { "version": "f531d13bdfe3f4f084aaa8acae2cb0f02295f5ae", "lessThan": "2255ed6adbc3100d2c4a83abd9d0396d04b87792", "status": "affected", "versionType": "git" }, { "version": "f531d13bdfe3f4f084aaa8acae2cb0f02295f5ae", "lessThan": "21f2fc49ca6faa393c31da33b8a4e6c41fc84c13", "status": "affected", "versionType": "git" }, { "version": "f531d13bdfe3f4f084aaa8acae2cb0f02295f5ae", "lessThan": "daf8e3b253aa760ff9e96c7768a464bc1d6b3c90", "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/xfrm/xfrm_nat_keepalive.c" ], "versions": [ { "version": "6.11", "status": "affected" }, { "version": "0", "lessThan": "6.11", "status": "unaffected", "versionType": "semver" }, { "version": "6.12.80", "lessThanOrEqual": "6.12.*", "status": "unaffected", "versionType": "semver" }, { "version": "6.18.21", "lessThanOrEqual": "6.18.*", "status": "unaffected", "versionType": "semver" }, { "version": "6.19.11", "lessThanOrEqual": "6.19.*", "status": "unaffected", "versionType": "semver" }, { "version": "7.0", "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": "6.11", "versionEndExcluding": "6.12.80" }, { "vulnerable": true, "criteria": "cpe:2.3:o:linux:linux_kernel:*:*:*:*:*:*:*:*", "versionStartIncluding": "6.11", "versionEndExcluding": "6.18.21" }, { "vulnerable": true, "criteria": "cpe:2.3:o:linux:linux_kernel:*:*:*:*:*:*:*:*", "versionStartIncluding": "6.11", "versionEndExcluding": "6.19.11" }, { "vulnerable": true, "criteria": "cpe:2.3:o:linux:linux_kernel:*:*:*:*:*:*:*:*", "versionStartIncluding": "6.11", "versionEndExcluding": "7.0" } ] } ] } ], "references": [ { "url": "https://git.kernel.org/stable/c/32d0f44c2f14d60fe8e920e69a28c11051543ec1" }, { "url": "https://git.kernel.org/stable/c/2255ed6adbc3100d2c4a83abd9d0396d04b87792" }, { "url": "https://git.kernel.org/stable/c/21f2fc49ca6faa393c31da33b8a4e6c41fc84c13" }, { "url": "https://git.kernel.org/stable/c/daf8e3b253aa760ff9e96c7768a464bc1d6b3c90" } ], "title": "xfrm: Fix work re-schedule after cancel in xfrm_nat_keepalive_net_fini()", "x_generator": { "engine": "bippy-1.2.0" } } } }