{"id":"CVE-2026-64581","revision":"eb48129ebdf9485cadeddb5889c710a1","records":[{"revision":"eb48129ebdf9485cadeddb5889c710a1","observedAt":"2026-10-23T15:48:27.903+00:00","statement":{"source":"cve-program","id":"CVE-2026-64581","aliases":[],"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":0,"publishedAt":"2026-08-05T08:09:35.556+00:00","modifiedAt":"2026-10-19T20:48:43.05+00:00","affected":[{"ecosystem":"Vendor product","name":"Linux","ranges":[],"versions":[],"rawVersionEvidence":"{\n \"product\": \"Linux\",\n \"vendor\": \"Linux\",\n \"defaultStatus\": \"unaffected\",\n \"repo\": \"https://git.kernel.org/pub/scm/linux/kernel/git/stable/linux.git\",\n \"programFiles\": [\n \"net/xfrm/xfrm_state.c\"\n ],\n \"versions\": [\n {\n \"version\": \"2b06cdf3e688b98fcc9945873b5d42792bd4eee0\",\n \"lessThan\": \"e8686fd8d18b99f3a9038683045b2f2338a7706d\",\n \"status\": \"affected\",\n \"versionType\": \"git\"\n },\n {\n \"version\": \"2b06cdf3e688b98fcc9945873b5d42792bd4eee0\",\n \"lessThan\": \"a9340ebdc13f8bb5063c0bc0b037ee7e640d4ae9\",\n \"status\": \"affected\",\n \"versionType\": \"git\"\n },\n {\n \"version\": \"2b06cdf3e688b98fcc9945873b5d42792bd4eee0\",\n \"lessThan\": \"f833821e4b52ab6335d443ede5fb79c38e61d19a\",\n \"status\": \"affected\",\n \"versionType\": \"git\"\n },\n {\n \"version\": \"2b06cdf3e688b98fcc9945873b5d42792bd4eee0\",\n \"lessThan\": \"f0ab9a71167bae308e05ab13b65e2007504a603f\",\n \"status\": \"affected\",\n \"versionType\": \"git\"\n },\n {\n \"version\": \"2b06cdf3e688b98fcc9945873b5d42792bd4eee0\",\n \"lessThan\": \"8dd8929b71c4f06c614f8f54c2cc070453faae16\",\n \"status\": \"affected\",\n \"versionType\": \"git\"\n },\n {\n \"version\": \"2b06cdf3e688b98fcc9945873b5d42792bd4eee0\",\n \"lessThan\": \"0ea8f06454012d9e7f9c6e6253df710949bf6294\",\n \"status\": \"affected\",\n \"versionType\": \"git\"\n },\n {\n \"version\": \"2b06cdf3e688b98fcc9945873b5d42792bd4eee0\",\n \"lessThan\": \"96b678d08268b5f5c6fc99d4289d9b7e334fc683\",\n \"status\": \"affected\",\n \"versionType\": \"git\"\n },\n {\n \"version\": \"2b06cdf3e688b98fcc9945873b5d42792bd4eee0\",\n \"lessThan\": \"c283e9ada7fcb7dd4b10592623086b2e6d2f9925\",\n \"status\": \"affected\",\n \"versionType\": \"git\"\n },\n {\n \"version\": \"72f157be2f81910ae759bfe2e5c2256fc4625645\",\n \"status\": \"affected\",\n \"versionType\": \"git\"\n },\n {\n \"version\": \"9e9fe58a92a46c6d154d2901735bf230d91b8507\",\n \"status\": \"affected\",\n \"versionType\": \"git\"\n },\n {\n \"version\": \"adc1ec6cdc20d430aa01b86497220709b9149466\",\n \"status\": \"affected\",\n \"versionType\": \"git\"\n },\n {\n \"version\": \"b54033eb1cfd77aba471269ddd804ed8d3e35dea\",\n \"status\": \"affected\",\n \"versionType\": \"git\"\n },\n {\n \"version\": \"c9e82cb34c3c2ee895af01bc899c6ed0bc6eb04a\",\n \"status\": \"affected\",\n \"versionType\": \"git\"\n },\n {\n \"version\": \"5eef9b51114fcc65651d671add52f267f91b9451\",\n \"status\": \"affected\",\n \"versionType\": \"git\"\n },\n {\n \"version\": \"3.16.52\",\n \"lessThan\": \"3.17\",\n \"status\": \"affected\",\n \"versionType\": \"semver\"\n },\n {\n \"version\": \"4.4.163\",\n \"lessThan\": \"4.5\",\n \"status\": \"affected\",\n \"versionType\": \"semver\"\n },\n {\n \"version\": \"3.18.101\",\n \"lessThan\": \"3.19\",\n \"status\": \"affected\",\n \"versionType\": \"semver\"\n },\n {\n \"version\": \"4.1.52\",\n \"lessThan\": \"4.2\",\n \"status\": \"affected\",\n \"versionType\": \"semver\"\n },\n {\n \"version\": \"4.4.123\",\n \"lessThan\": \"4.5\",\n \"status\": \"affected\",\n \"versionType\": \"semver\"\n },\n {\n \"version\": \"4.9.89\",\n \"lessThan\": \"4.10\",\n \"status\": \"affected\",\n \"versionType\": \"semver\"\n }\n ]\n }"},{"ecosystem":"Vendor product","name":"Linux","ranges":[],"versions":[],"rawVersionEvidence":"{\n \"product\": \"Linux\",\n \"vendor\": \"Linux\",\n \"defaultStatus\": \"affected\",\n \"repo\": \"https://git.kernel.org/pub/scm/linux/kernel/git/stable/linux.git\",\n \"programFiles\": [\n \"net/xfrm/xfrm_state.c\"\n ],\n \"versions\": [\n {\n \"version\": \"4.14\",\n \"status\": \"affected\"\n },\n {\n \"version\": \"0\",\n \"lessThan\": \"4.14\",\n \"status\": \"unaffected\",\n \"versionType\": \"semver\"\n },\n {\n \"version\": \"5.10.267\",\n \"lessThanOrEqual\": \"5.10.*\",\n \"status\": \"unaffected\",\n \"versionType\": \"semver\"\n },\n {\n \"version\": \"5.15.218\",\n \"lessThanOrEqual\": \"5.15.*\",\n \"status\": \"unaffected\",\n \"versionType\": \"semver\"\n },\n {\n \"version\": \"6.1.185\",\n \"lessThanOrEqual\": \"6.1.*\",\n \"status\": \"unaffected\",\n \"versionType\": \"semver\"\n },\n {\n \"version\": \"6.6.154\",\n \"lessThanOrEqual\": \"6.6.*\",\n \"status\": \"unaffected\",\n \"versionType\": \"semver\"\n },\n {\n \"version\": \"6.12.106\",\n \"lessThanOrEqual\": \"6.12.*\",\n \"status\": \"unaffected\",\n \"versionType\": \"semver\"\n },\n {\n \"version\": \"6.18.47\",\n \"lessThanOrEqual\": \"6.18.*\",\n \"status\": \"unaffected\",\n \"versionType\": \"semver\"\n },\n {\n \"version\": \"7.1.6\",\n \"lessThanOrEqual\": \"7.1.*\",\n \"status\": \"unaffected\",\n \"versionType\": \"semver\"\n },\n {\n \"version\": \"7.2\",\n \"lessThanOrEqual\": \"*\",\n \"status\": \"unaffected\",\n \"versionType\": \"original_commit_for_fix\"\n }\n ]\n }"}],"metrics":[{"system":"CVSS 3.1","vector":"CVSS:3.1/AV:L/AC:L/PR:L/UI:N/S:U/C:H/I:H/A:H","score":7.8,"severity":"HIGH"}],"references":["https://git.kernel.org/stable/c/e8686fd8d18b99f3a9038683045b2f2338a7706d","https://git.kernel.org/stable/c/a9340ebdc13f8bb5063c0bc0b037ee7e640d4ae9","https://git.kernel.org/stable/c/f833821e4b52ab6335d443ede5fb79c38e61d19a","https://git.kernel.org/stable/c/f0ab9a71167bae308e05ab13b65e2007504a603f","https://git.kernel.org/stable/c/8dd8929b71c4f06c614f8f54c2cc070453faae16","https://git.kernel.org/stable/c/0ea8f06454012d9e7f9c6e6253df710949bf6294","https://git.kernel.org/stable/c/96b678d08268b5f5c6fc99d4289d9b7e334fc683","https://git.kernel.org/stable/c/c283e9ada7fcb7dd4b10592623086b2e6d2f9925"],"sourceUrl":"https://www.cve.org/CVERecord?id=CVE-2026-64581","license":"CVE Program Terms of Use","key":"cve-program:CVE-2026-64581","identifiers":["CVE-2026-64581"]},"retained":false,"historicalAffected":[]}],"coverage":[]}