{"api_version":"1","generated_at":"2026-08-06T02:59:05+00:00","cve":"CVE-2026-64581","urls":{"html":"https://cve.report/CVE-2026-64581","api":"https://cve.report/api/cve/CVE-2026-64581.json","docs":"https://cve.report/api","cve_org":"https://www.cve.org/CVERecord?id=CVE-2026-64581","nvd":"https://nvd.nist.gov/vuln/detail/CVE-2026-64581"},"summary":{"title":"xfrm: fix sk_dst_cache double-free in xfrm_user_policy()","description":"In the Linux kernel, the following vulnerability has been resolved:\n\nxfrm: fix sk_dst_cache double-free in xfrm_user_policy()\n\nxfrm_user_policy() clears the socket dst cache with __sk_dst_reset(),\ni.e. the non-atomic __sk_dst_set(sk, NULL): it reads sk_dst_cache with\nrcu_dereference_protected(), stores NULL and dst_release()s the old dst.\nThat is only safe if no other thread modifies sk_dst_cache concurrently.\n\nFor a connected UDP socket that does not hold: the transmit fast path\n(udp_sendmsg -> sk_dst_check -> sk_dst_reset) resets the cache locklessly\nwith an atomic xchg(). A per-socket policy change racing a send can make\nboth sides observe the same old dst and each dst_release() it, dropping\nthe socket's single reference twice and freeing the xfrm_dst bundle while\nit is still referenced:\n\n  BUG: KASAN: slab-use-after-free in dst_release\n  Write of size 4 at addr ffff88801897b6c0 by task exploit/155\n  Call Trace:\n   ...\n   dst_release (... ./include/linux/rcuref.h:109)\n   xfrm_user_policy (./include/net/sock.h:2239 ./include/net/sock.h:2256 net/xfrm/xfrm_state.c:3053)\n   do_ip_setsockopt (net/ipv4/ip_sockglue.c:1347)\n   ip_setsockopt (net/ipv4/ip_sockglue.c:1417)\n   do_sock_setsockopt (net/socket.c:2368)\n   __sys_setsockopt (net/socket.c:2393)\n   __x64_sys_setsockopt (net/socket.c:2396)\n   do_syscall_64 (arch/x86/entry/syscall_64.c:94)\n   entry_SYSCALL_64_after_hwframe (arch/x86/entry/entry_64.S:121)\n\nReachable by an unprivileged user via a user+network namespace.\n\nUse the atomic sk_dst_reset() so the cache is cleared and released with a\nsingle xchg(): whichever side wins releases the dst once, the other sees\nNULL and does nothing. Behaviour is otherwise unchanged.","state":"PUBLISHED","assigner":"Linux","published_at":"2026-08-05 08:16:38","updated_at":"2026-08-05 08:16:38"},"problem_types":[],"metrics":[],"references":[{"url":"https://git.kernel.org/stable/c/96b678d08268b5f5c6fc99d4289d9b7e334fc683","name":"https://git.kernel.org/stable/c/96b678d08268b5f5c6fc99d4289d9b7e334fc683","refsource":"416baaa9-dc9f-4396-8d5f-8c081fb06d67","tags":[],"title":"","mime":"","httpstatus":"","archivestatus":"0"},{"url":"https://git.kernel.org/stable/c/c283e9ada7fcb7dd4b10592623086b2e6d2f9925","name":"https://git.kernel.org/stable/c/c283e9ada7fcb7dd4b10592623086b2e6d2f9925","refsource":"416baaa9-dc9f-4396-8d5f-8c081fb06d67","tags":[],"title":"","mime":"","httpstatus":"","archivestatus":"0"},{"url":"https://www.cve.org/CVERecord?id=CVE-2026-64581","name":"CVE Program record","refsource":"CVE.ORG","tags":["canonical"]},{"url":"https://nvd.nist.gov/vuln/detail/CVE-2026-64581","name":"NVD vulnerability detail","refsource":"NVD","tags":["canonical","analysis"]}],"affected":[{"source":"CNA","vendor":"Linux","product":"Linux","version":"affected 2b06cdf3e688b98fcc9945873b5d42792bd4eee0 96b678d08268b5f5c6fc99d4289d9b7e334fc683 git","platforms":[]},{"source":"CNA","vendor":"Linux","product":"Linux","version":"affected 2b06cdf3e688b98fcc9945873b5d42792bd4eee0 c283e9ada7fcb7dd4b10592623086b2e6d2f9925 git","platforms":[]},{"source":"CNA","vendor":"Linux","product":"Linux","version":"affected 72f157be2f81910ae759bfe2e5c2256fc4625645 git","platforms":[]},{"source":"CNA","vendor":"Linux","product":"Linux","version":"affected 9e9fe58a92a46c6d154d2901735bf230d91b8507 git","platforms":[]},{"source":"CNA","vendor":"Linux","product":"Linux","version":"affected adc1ec6cdc20d430aa01b86497220709b9149466 git","platforms":[]},{"source":"CNA","vendor":"Linux","product":"Linux","version":"affected b54033eb1cfd77aba471269ddd804ed8d3e35dea git","platforms":[]},{"source":"CNA","vendor":"Linux","product":"Linux","version":"affected c9e82cb34c3c2ee895af01bc899c6ed0bc6eb04a git","platforms":[]},{"source":"CNA","vendor":"Linux","product":"Linux","version":"affected 5eef9b51114fcc65651d671add52f267f91b9451 git","platforms":[]},{"source":"CNA","vendor":"Linux","product":"Linux","version":"affected 3.16.52 3.17 semver","platforms":[]},{"source":"CNA","vendor":"Linux","product":"Linux","version":"affected 4.4.163 4.5 semver","platforms":[]},{"source":"CNA","vendor":"Linux","product":"Linux","version":"affected 3.18.101 3.19 semver","platforms":[]},{"source":"CNA","vendor":"Linux","product":"Linux","version":"affected 4.1.52 4.2 semver","platforms":[]},{"source":"CNA","vendor":"Linux","product":"Linux","version":"affected 4.4.123 4.5 semver","platforms":[]},{"source":"CNA","vendor":"Linux","product":"Linux","version":"affected 4.9.89 4.10 semver","platforms":[]},{"source":"CNA","vendor":"Linux","product":"Linux","version":"affected 4.14","platforms":[]},{"source":"CNA","vendor":"Linux","product":"Linux","version":"unaffected 4.14 semver","platforms":[]},{"source":"CNA","vendor":"Linux","product":"Linux","version":"unaffected 7.1.6 7.1.* semver","platforms":[]},{"source":"CNA","vendor":"Linux","product":"Linux","version":"unaffected 7.2-rc4 * original_commit_for_fix","platforms":[]}],"timeline":[],"solutions":[],"workarounds":[],"exploits":[],"credits":[],"nvd_cpes":[],"vendor_comments":[],"enrichments":{"kev":null,"epss":{"cve_year":"2026","cve_id":"64581","cve":"CVE-2026-64581","epss":"0.001450000","percentile":"0.042100000","score_date":"2026-08-05","updated_at":"2026-08-06 00:00:32"},"legacy_qids":[]},"source_records":{"cve_program":{"containers":{"cna":{"affected":[{"defaultStatus":"unaffected","product":"Linux","programFiles":["net/xfrm/xfrm_state.c"],"repo":"https://git.kernel.org/pub/scm/linux/kernel/git/stable/linux.git","vendor":"Linux","versions":[{"lessThan":"96b678d08268b5f5c6fc99d4289d9b7e334fc683","status":"affected","version":"2b06cdf3e688b98fcc9945873b5d42792bd4eee0","versionType":"git"},{"lessThan":"c283e9ada7fcb7dd4b10592623086b2e6d2f9925","status":"affected","version":"2b06cdf3e688b98fcc9945873b5d42792bd4eee0","versionType":"git"},{"status":"affected","version":"72f157be2f81910ae759bfe2e5c2256fc4625645","versionType":"git"},{"status":"affected","version":"9e9fe58a92a46c6d154d2901735bf230d91b8507","versionType":"git"},{"status":"affected","version":"adc1ec6cdc20d430aa01b86497220709b9149466","versionType":"git"},{"status":"affected","version":"b54033eb1cfd77aba471269ddd804ed8d3e35dea","versionType":"git"},{"status":"affected","version":"c9e82cb34c3c2ee895af01bc899c6ed0bc6eb04a","versionType":"git"},{"status":"affected","version":"5eef9b51114fcc65651d671add52f267f91b9451","versionType":"git"},{"lessThan":"3.17","status":"affected","version":"3.16.52","versionType":"semver"},{"lessThan":"4.5","status":"affected","version":"4.4.163","versionType":"semver"},{"lessThan":"3.19","status":"affected","version":"3.18.101","versionType":"semver"},{"lessThan":"4.2","status":"affected","version":"4.1.52","versionType":"semver"},{"lessThan":"4.5","status":"affected","version":"4.4.123","versionType":"semver"},{"lessThan":"4.10","status":"affected","version":"4.9.89","versionType":"semver"}]},{"defaultStatus":"affected","product":"Linux","programFiles":["net/xfrm/xfrm_state.c"],"repo":"https://git.kernel.org/pub/scm/linux/kernel/git/stable/linux.git","vendor":"Linux","versions":[{"status":"affected","version":"4.14"},{"lessThan":"4.14","status":"unaffected","version":"0","versionType":"semver"},{"lessThanOrEqual":"7.1.*","status":"unaffected","version":"7.1.6","versionType":"semver"},{"lessThanOrEqual":"*","status":"unaffected","version":"7.2-rc4","versionType":"original_commit_for_fix"}]}],"cpeApplicability":[{"nodes":[{"cpeMatch":[{"criteria":"cpe:2.3:o:linux:linux_kernel:*:*:*:*:*:*:*:*","versionEndExcluding":"7.1.6","versionStartIncluding":"4.14","vulnerable":true},{"criteria":"cpe:2.3:o:linux:linux_kernel:*:*:*:*:*:*:*:*","versionEndExcluding":"7.2-rc4","versionStartIncluding":"4.14","vulnerable":true},{"criteria":"cpe:2.3:o:linux:linux_kernel:*:*:*:*:*:*:*:*","versionStartIncluding":"3.16.52","vulnerable":true},{"criteria":"cpe:2.3:o:linux:linux_kernel:*:*:*:*:*:*:*:*","versionStartIncluding":"4.4.163","vulnerable":true},{"criteria":"cpe:2.3:o:linux:linux_kernel:*:*:*:*:*:*:*:*","versionStartIncluding":"3.18.101","vulnerable":true},{"criteria":"cpe:2.3:o:linux:linux_kernel:*:*:*:*:*:*:*:*","versionStartIncluding":"4.1.52","vulnerable":true},{"criteria":"cpe:2.3:o:linux:linux_kernel:*:*:*:*:*:*:*:*","versionStartIncluding":"4.4.123","vulnerable":true},{"criteria":"cpe:2.3:o:linux:linux_kernel:*:*:*:*:*:*:*:*","versionStartIncluding":"4.9.89","vulnerable":true}],"negate":false,"operator":"OR"}]}],"descriptions":[{"lang":"en","value":"In the Linux kernel, the following vulnerability has been resolved:\n\nxfrm: fix sk_dst_cache double-free in xfrm_user_policy()\n\nxfrm_user_policy() clears the socket dst cache with __sk_dst_reset(),\ni.e. the non-atomic __sk_dst_set(sk, NULL): it reads sk_dst_cache with\nrcu_dereference_protected(), stores NULL and dst_release()s the old dst.\nThat is only safe if no other thread modifies sk_dst_cache concurrently.\n\nFor a connected UDP socket that does not hold: the transmit fast path\n(udp_sendmsg -> sk_dst_check -> sk_dst_reset) resets the cache locklessly\nwith an atomic xchg(). A per-socket policy change racing a send can make\nboth sides observe the same old dst and each dst_release() it, dropping\nthe socket's single reference twice and freeing the xfrm_dst bundle while\nit is still referenced:\n\n  BUG: KASAN: slab-use-after-free in dst_release\n  Write of size 4 at addr ffff88801897b6c0 by task exploit/155\n  Call Trace:\n   ...\n   dst_release (... ./include/linux/rcuref.h:109)\n   xfrm_user_policy (./include/net/sock.h:2239 ./include/net/sock.h:2256 net/xfrm/xfrm_state.c:3053)\n   do_ip_setsockopt (net/ipv4/ip_sockglue.c:1347)\n   ip_setsockopt (net/ipv4/ip_sockglue.c:1417)\n   do_sock_setsockopt (net/socket.c:2368)\n   __sys_setsockopt (net/socket.c:2393)\n   __x64_sys_setsockopt (net/socket.c:2396)\n   do_syscall_64 (arch/x86/entry/syscall_64.c:94)\n   entry_SYSCALL_64_after_hwframe (arch/x86/entry/entry_64.S:121)\n\nReachable by an unprivileged user via a user+network namespace.\n\nUse the atomic sk_dst_reset() so the cache is cleared and released with a\nsingle xchg(): whichever side wins releases the dst once, the other sees\nNULL and does nothing. Behaviour is otherwise unchanged."}],"providerMetadata":{"dateUpdated":"2026-08-05T08:09:35.556Z","orgId":"416baaa9-dc9f-4396-8d5f-8c081fb06d67","shortName":"Linux"},"references":[{"url":"https://git.kernel.org/stable/c/96b678d08268b5f5c6fc99d4289d9b7e334fc683"},{"url":"https://git.kernel.org/stable/c/c283e9ada7fcb7dd4b10592623086b2e6d2f9925"}],"title":"xfrm: fix sk_dst_cache double-free in xfrm_user_policy()","x_generator":{"engine":"bippy-1.2.0"}}},"cveMetadata":{"assignerOrgId":"416baaa9-dc9f-4396-8d5f-8c081fb06d67","assignerShortName":"Linux","cveId":"CVE-2026-64581","datePublished":"2026-08-05T08:09:35.556Z","dateReserved":"2026-07-19T15:36:31.798Z","dateUpdated":"2026-08-05T08:09:35.556Z","state":"PUBLISHED"},"dataType":"CVE_RECORD","dataVersion":"5.2"},"nvd":{"publishedDate":"2026-08-05 08:16:38","lastModifiedDate":"2026-08-05 08:16:38","problem_types":[],"metrics":[],"configurations":[]},"legacy_mitre":{"record":{"CveYear":"2026","CveId":"64581","Ordinal":"1","Title":"xfrm: fix sk_dst_cache double-free in xfrm_user_policy()","CVE":"CVE-2026-64581","Year":"2026"},"notes":[{"CveYear":"2026","CveId":"64581","Ordinal":"1","NoteData":"In the Linux kernel, the following vulnerability has been resolved:\n\nxfrm: fix sk_dst_cache double-free in xfrm_user_policy()\n\nxfrm_user_policy() clears the socket dst cache with __sk_dst_reset(),\ni.e. the non-atomic __sk_dst_set(sk, NULL): it reads sk_dst_cache with\nrcu_dereference_protected(), stores NULL and dst_release()s the old dst.\nThat is only safe if no other thread modifies sk_dst_cache concurrently.\n\nFor a connected UDP socket that does not hold: the transmit fast path\n(udp_sendmsg -> sk_dst_check -> sk_dst_reset) resets the cache locklessly\nwith an atomic xchg(). A per-socket policy change racing a send can make\nboth sides observe the same old dst and each dst_release() it, dropping\nthe socket's single reference twice and freeing the xfrm_dst bundle while\nit is still referenced:\n\n  BUG: KASAN: slab-use-after-free in dst_release\n  Write of size 4 at addr ffff88801897b6c0 by task exploit/155\n  Call Trace:\n   ...\n   dst_release (... ./include/linux/rcuref.h:109)\n   xfrm_user_policy (./include/net/sock.h:2239 ./include/net/sock.h:2256 net/xfrm/xfrm_state.c:3053)\n   do_ip_setsockopt (net/ipv4/ip_sockglue.c:1347)\n   ip_setsockopt (net/ipv4/ip_sockglue.c:1417)\n   do_sock_setsockopt (net/socket.c:2368)\n   __sys_setsockopt (net/socket.c:2393)\n   __x64_sys_setsockopt (net/socket.c:2396)\n   do_syscall_64 (arch/x86/entry/syscall_64.c:94)\n   entry_SYSCALL_64_after_hwframe (arch/x86/entry/entry_64.S:121)\n\nReachable by an unprivileged user via a user+network namespace.\n\nUse the atomic sk_dst_reset() so the cache is cleared and released with a\nsingle xchg(): whichever side wins releases the dst once, the other sees\nNULL and does nothing. Behaviour is otherwise unchanged.","Type":"Description","Title":"xfrm: fix sk_dst_cache double-free in xfrm_user_policy()"}]}}}