{ "dataType": "CVE_RECORD", "dataVersion": "5.2", "cveMetadata": { "cveId": "CVE-2026-43091", "assignerOrgId": "416baaa9-dc9f-4396-8d5f-8c081fb06d67", "state": "PUBLISHED", "assignerShortName": "Linux", "dateReserved": "2026-05-01T14:12:55.984Z", "datePublished": "2026-05-06T07:40:23.955Z", "dateUpdated": "2026-08-05T12:25:52.160Z" }, "containers": { "cna": { "providerMetadata": { "orgId": "416baaa9-dc9f-4396-8d5f-8c081fb06d67", "shortName": "Linux", "dateUpdated": "2026-08-05T12:25:52.160Z" }, "descriptions": [ { "lang": "en", "value": "In the Linux kernel, the following vulnerability has been resolved:\n\nxfrm: Wait for RCU readers during policy netns exit\n\nxfrm_policy_fini() frees the policy_bydst hash tables after flushing the\npolicy work items and deleting all policies, but it does not wait for\nconcurrent RCU readers to leave their read-side critical sections first.\n\nThe policy_bydst tables are published via rcu_assign_pointer() and are\nlooked up through rcu_dereference_check(), so netns teardown must also\nwait for an RCU grace period before freeing the table memory.\n\nFix this by adding synchronize_rcu() before freeing the policy hash tables." } ], "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 requires local control of a network namespace/XFRM policy state and concurrent namespace teardown; remote packets can exercise XFRM policy lookups, but a remote attacker cannot normally trigger the required netns exit.\nAC:L - The race is attacker-controllable by creating XFRM policies, generating policy lookups, and tearing down the namespace concurrently; no rare configuration or victim-controlled timing is required beyond winning a repeatable local race.\nPR:L - XFRM netlink operations require CAP_NET_ADMIN in the target network namespace, but an unprivileged local user can obtain that in a new user+network namespace on common userns-enabled systems.\nUI:N - No victim action is required once the local attacker can run code and issue the relevant namespace, netlink, and traffic operations.\nS:U - The impact is within the kernel security authority; this is a standard kernel memory-safety issue rather than a VM, IOMMU, or separate-scope escape.\nC:H - This is a use-after-free of an RCU-published XFRM policy hash table, and stale readers may dereference reallocated attacker-influenced memory during policy lookup.\nI:H - As a kernel UAF in a list traversal path that can reach policy object handling, the freed memory can plausibly be shaped into fake list/policy data and leveraged for kernel memory corruption.\nA:H - At minimum, dereferencing freed hash-table memory during packet or route policy lookup can trigger a kernel oops or panic, causing high availability impact." } ] } ], "affected": [ { "product": "Linux", "vendor": "Linux", "defaultStatus": "unaffected", "repo": "https://git.kernel.org/pub/scm/linux/kernel/git/stable/linux.git", "programFiles": [ "net/xfrm/xfrm_policy.c" ], "versions": [ { "version": "e1e551bc56302b80ff930c966f9985095fb1b70d", "lessThan": "b66920a3348c0f63ba18365248fa21fbf0b3a937", "status": "affected", "versionType": "git" }, { "version": "e1e551bc56302b80ff930c966f9985095fb1b70d", "lessThan": "438b1f668ad58f46ce699bb48e4698a7839e3f9e", "status": "affected", "versionType": "git" }, { "version": "e1e551bc56302b80ff930c966f9985095fb1b70d", "lessThan": "3733fce2871c9bca9dd18a1a23b1432ea215a094", "status": "affected", "versionType": "git" }, { "version": "e1e551bc56302b80ff930c966f9985095fb1b70d", "lessThan": "33a3149dd81a1e2f52b80ee1e0fc380b39f3d028", "status": "affected", "versionType": "git" }, { "version": "e1e551bc56302b80ff930c966f9985095fb1b70d", "lessThan": "069daad4f2ae9c5c108131995529d5f02392c446", "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_policy.c" ], "versions": [ { "version": "4.9", "status": "affected" }, { "version": "0", "lessThan": "4.9", "status": "unaffected", "versionType": "semver" }, { "version": "6.6.136", "lessThanOrEqual": "6.6.*", "status": "unaffected", "versionType": "semver" }, { "version": "6.12.83", "lessThanOrEqual": "6.12.*", "status": "unaffected", "versionType": "semver" }, { "version": "6.18.24", "lessThanOrEqual": "6.18.*", "status": "unaffected", "versionType": "semver" }, { "version": "6.19.14", "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": "4.9", "versionEndExcluding": "6.6.136" }, { "vulnerable": true, "criteria": "cpe:2.3:o:linux:linux_kernel:*:*:*:*:*:*:*:*", "versionStartIncluding": "4.9", "versionEndExcluding": "6.12.83" }, { "vulnerable": true, "criteria": "cpe:2.3:o:linux:linux_kernel:*:*:*:*:*:*:*:*", "versionStartIncluding": "4.9", "versionEndExcluding": "6.18.24" }, { "vulnerable": true, "criteria": "cpe:2.3:o:linux:linux_kernel:*:*:*:*:*:*:*:*", "versionStartIncluding": "4.9", "versionEndExcluding": "6.19.14" }, { "vulnerable": true, "criteria": "cpe:2.3:o:linux:linux_kernel:*:*:*:*:*:*:*:*", "versionStartIncluding": "4.9", "versionEndExcluding": "7.0" } ] } ] } ], "references": [ { "url": "https://git.kernel.org/stable/c/b66920a3348c0f63ba18365248fa21fbf0b3a937" }, { "url": "https://git.kernel.org/stable/c/438b1f668ad58f46ce699bb48e4698a7839e3f9e" }, { "url": "https://git.kernel.org/stable/c/3733fce2871c9bca9dd18a1a23b1432ea215a094" }, { "url": "https://git.kernel.org/stable/c/33a3149dd81a1e2f52b80ee1e0fc380b39f3d028" }, { "url": "https://git.kernel.org/stable/c/069daad4f2ae9c5c108131995529d5f02392c446" } ], "title": "xfrm: Wait for RCU readers during policy netns exit", "x_generator": { "engine": "bippy-1.2.0" } } } }