{ "dataType": "CVE_RECORD", "dataVersion": "5.2", "cveMetadata": { "cveId": "CVE-2026-64581", "assignerOrgId": "416baaa9-dc9f-4396-8d5f-8c081fb06d67", "state": "PUBLISHED", "assignerShortName": "Linux", "dateReserved": "2026-07-19T15:36:31.798Z", "datePublished": "2026-08-05T08:09:35.556Z", "dateUpdated": "2026-08-27T12:39:44.254Z" }, "containers": { "cna": { "providerMetadata": { "orgId": "416baaa9-dc9f-4396-8d5f-8c081fb06d67", "shortName": "Linux", "dateUpdated": "2026-08-27T12:39:44.254Z" }, "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." } ], "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 - Triggered via setsockopt(IP_XFRM_POLICY/IP_IPSEC_POLICY) on a local socket racing concurrent udp_sendmsg; entry is a local syscall path (do_ip_setsockopt -> xfrm_user_policy), not packet processing.\nAC:L - Attacker controls both sides of the race (one thread setsockopt to clear/apply per-socket xfrm policy, another sendmsg on the same connected UDP socket) and can create the obsolete xfrm_dst precondition in their netns, retrying until the double dst_release wins.\nPR:L - Path requires CAP_NET_ADMIN checked with sockopt_ns_capable(sock_net(sk)->user_ns), which an unprivileged user obtains via user+network namespaces; the fix commit explicitly states this reachability.\nUI:N - Exploitation uses only the attacker's own socket, threads, and setsockopt/sendmsg loops; no victim action or cooperation is required.\nS:U - Double-free/UAF of the socket's dst_entry/xfrm_dst is standard local kernel memory corruption within the host kernel authority, not a VM escape or other cross-boundary impact.\nC:H - Double dst_release frees the xfrm_dst slab object while still referenced, yielding a use-after-free that can be reclaimed/sprayed to disclose kernel memory via corrupted dst contents and ops.\nI:H - The UAF targets a dst_entry with function pointers (ops/input/output) used on transmit, enabling heap reuse for arbitrary write and control-flow hijack consistent with comparable sk_dst_cache races.\nA:H - The KASAN slab-use-after-free in dst_release demonstrates kernel memory corruption that can oops/panic, and the attacker can repeat the race freely." } ] } ], "affected": [ { "product": "Linux", "vendor": "Linux", "defaultStatus": "unaffected", "repo": "https://git.kernel.org/pub/scm/linux/kernel/git/stable/linux.git", "programFiles": [ "net/xfrm/xfrm_state.c" ], "versions": [ { "version": "2b06cdf3e688b98fcc9945873b5d42792bd4eee0", "lessThan": "e8686fd8d18b99f3a9038683045b2f2338a7706d", "status": "affected", "versionType": "git" }, { "version": "2b06cdf3e688b98fcc9945873b5d42792bd4eee0", "lessThan": "a9340ebdc13f8bb5063c0bc0b037ee7e640d4ae9", "status": "affected", "versionType": "git" }, { "version": "2b06cdf3e688b98fcc9945873b5d42792bd4eee0", "lessThan": "f833821e4b52ab6335d443ede5fb79c38e61d19a", "status": "affected", "versionType": "git" }, { "version": "2b06cdf3e688b98fcc9945873b5d42792bd4eee0", "lessThan": "f0ab9a71167bae308e05ab13b65e2007504a603f", "status": "affected", "versionType": "git" }, { "version": "2b06cdf3e688b98fcc9945873b5d42792bd4eee0", "lessThan": "8dd8929b71c4f06c614f8f54c2cc070453faae16", "status": "affected", "versionType": "git" }, { "version": "2b06cdf3e688b98fcc9945873b5d42792bd4eee0", "lessThan": "0ea8f06454012d9e7f9c6e6253df710949bf6294", "status": "affected", "versionType": "git" }, { "version": "2b06cdf3e688b98fcc9945873b5d42792bd4eee0", "lessThan": "96b678d08268b5f5c6fc99d4289d9b7e334fc683", "status": "affected", "versionType": "git" }, { "version": "2b06cdf3e688b98fcc9945873b5d42792bd4eee0", "lessThan": "c283e9ada7fcb7dd4b10592623086b2e6d2f9925", "status": "affected", "versionType": "git" }, { "version": "72f157be2f81910ae759bfe2e5c2256fc4625645", "status": "affected", "versionType": "git" }, { "version": "9e9fe58a92a46c6d154d2901735bf230d91b8507", "status": "affected", "versionType": "git" }, { "version": "adc1ec6cdc20d430aa01b86497220709b9149466", "status": "affected", "versionType": "git" }, { "version": "b54033eb1cfd77aba471269ddd804ed8d3e35dea", "status": "affected", "versionType": "git" }, { "version": "c9e82cb34c3c2ee895af01bc899c6ed0bc6eb04a", "status": "affected", "versionType": "git" }, { "version": "5eef9b51114fcc65651d671add52f267f91b9451", "status": "affected", "versionType": "git" }, { "version": "3.16.52", "lessThan": "3.17", "status": "affected", "versionType": "semver" }, { "version": "4.4.163", "lessThan": "4.5", "status": "affected", "versionType": "semver" }, { "version": "3.18.101", "lessThan": "3.19", "status": "affected", "versionType": "semver" }, { "version": "4.1.52", "lessThan": "4.2", "status": "affected", "versionType": "semver" }, { "version": "4.4.123", "lessThan": "4.5", "status": "affected", "versionType": "semver" }, { "version": "4.9.89", "lessThan": "4.10", "status": "affected", "versionType": "semver" } ] }, { "product": "Linux", "vendor": "Linux", "defaultStatus": "affected", "repo": "https://git.kernel.org/pub/scm/linux/kernel/git/stable/linux.git", "programFiles": [ "net/xfrm/xfrm_state.c" ], "versions": [ { "version": "4.14", "status": "affected" }, { "version": "0", "lessThan": "4.14", "status": "unaffected", "versionType": "semver" }, { "version": "5.10.267", "lessThanOrEqual": "5.10.*", "status": "unaffected", "versionType": "semver" }, { "version": "5.15.218", "lessThanOrEqual": "5.15.*", "status": "unaffected", "versionType": "semver" }, { "version": "6.1.185", "lessThanOrEqual": "6.1.*", "status": "unaffected", "versionType": "semver" }, { "version": "6.6.154", "lessThanOrEqual": "6.6.*", "status": "unaffected", "versionType": "semver" }, { "version": "6.12.106", "lessThanOrEqual": "6.12.*", "status": "unaffected", "versionType": "semver" }, { "version": "6.18.47", "lessThanOrEqual": "6.18.*", "status": "unaffected", "versionType": "semver" }, { "version": "7.1.6", "lessThanOrEqual": "7.1.*", "status": "unaffected", "versionType": "semver" }, { "version": "7.2", "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": "4.14", "versionEndExcluding": "5.10.267" }, { "vulnerable": true, "criteria": "cpe:2.3:o:linux:linux_kernel:*:*:*:*:*:*:*:*", "versionStartIncluding": "4.14", "versionEndExcluding": "5.15.218" }, { "vulnerable": true, "criteria": "cpe:2.3:o:linux:linux_kernel:*:*:*:*:*:*:*:*", "versionStartIncluding": "4.14", "versionEndExcluding": "6.1.185" }, { "vulnerable": true, "criteria": "cpe:2.3:o:linux:linux_kernel:*:*:*:*:*:*:*:*", "versionStartIncluding": "4.14", "versionEndExcluding": "6.6.154" }, { "vulnerable": true, "criteria": "cpe:2.3:o:linux:linux_kernel:*:*:*:*:*:*:*:*", "versionStartIncluding": "4.14", "versionEndExcluding": "6.12.106" }, { "vulnerable": true, "criteria": "cpe:2.3:o:linux:linux_kernel:*:*:*:*:*:*:*:*", "versionStartIncluding": "4.14", "versionEndExcluding": "6.18.47" }, { "vulnerable": true, "criteria": "cpe:2.3:o:linux:linux_kernel:*:*:*:*:*:*:*:*", "versionStartIncluding": "4.14", "versionEndExcluding": "7.1.6" }, { "vulnerable": true, "criteria": "cpe:2.3:o:linux:linux_kernel:*:*:*:*:*:*:*:*", "versionStartIncluding": "4.14", "versionEndExcluding": "7.2" }, { "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" } ] } ] } ], "references": [ { "url": "https://git.kernel.org/stable/c/e8686fd8d18b99f3a9038683045b2f2338a7706d" }, { "url": "https://git.kernel.org/stable/c/a9340ebdc13f8bb5063c0bc0b037ee7e640d4ae9" }, { "url": "https://git.kernel.org/stable/c/f833821e4b52ab6335d443ede5fb79c38e61d19a" }, { "url": "https://git.kernel.org/stable/c/f0ab9a71167bae308e05ab13b65e2007504a603f" }, { "url": "https://git.kernel.org/stable/c/8dd8929b71c4f06c614f8f54c2cc070453faae16" }, { "url": "https://git.kernel.org/stable/c/0ea8f06454012d9e7f9c6e6253df710949bf6294" }, { "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" } } } }