xfrm: fix sk_dst_cache double-free in xfrm_user_policy()
In the Linux kernel, the following vulnerability has been resolved: xfrm: fix sk_dst_cache double-free in xfrm_user_policy() xfrm_user_policy() clears the socket dst cache with __sk_dst_reset(), i.e. the non-atomic __sk_dst_set(sk, NULL): it reads sk_dst_cache with rcu_dereference_protected(), stores NULL and dst_release()s the old dst. That is only safe if no other thread modifies sk_dst_cache concurrently. For a connected UDP socket that does not hold: the transmit fast path (udp_sendmsg -> sk_dst_check -> sk_dst_reset) resets the cache locklessly with an atomic xchg(). A per-socket policy change racing a send can make both sides observe the same old dst and each dst_release() it, dropping the socket's single reference twice and freeing the xfrm_dst bundle while it is still referenced: BUG: KASAN: slab-use-after-free in dst_release Write of size 4 at addr ffff88801897b6c0 by task exploit/155 Call Trace: ... dst_release (... ./include/linux/rcuref.h:109) xfrm_user_policy (./include/net/sock.h:2239 ./include/net/sock.h:2256 net/xfrm/xfrm_state.c:3053) do_ip_setsockopt (net/ipv4/ip_sockglue.c:1347) ip_setsockopt (net/ipv4/ip_sockglue.c:1417) do_sock_setsockopt (net/socket.c:2368) __sys_setsockopt (net/socket.c:2393) __x64_sys_setsockopt (net/socket.c:2396) do_syscall_64 (arch/x86/entry/syscall_64.c:94) entry_SYSCALL_64_after_hwframe (arch/x86/entry/entry_64.S:121) Reachable by an unprivileged user via a user+network namespace. Use the atomic sk_dst_reset() so the cache is clea
CVE-2026-64581
Primary source · Revision 1
Imported from structured advisory data. Source references identify upstream records or fields; verify affected versions and your deployed configuration.
Security context
Source reference: cve:CVE-2026-64581
Linux
Source reference: /containers/cna/affected/0/product
- Affected versions
- Not stated in this record
- Fixed versions
- Not stated in this record
- Prerequisites
- Not stated in this record
Linux
Source reference: /containers/cna/affected/1/product
- Affected versions
- Not stated in this record
- Fixed versions
- Not stated in this record
- Prerequisites
- Not stated in this record
Structured affected-version data
Original package identities and version rules from this source.
[
{
"repo": "https://git.kernel.org/pub/scm/linux/kernel/git/stable/linux.git",
"vendor": "Linux",
"product": "Linux",
"versions": [
{
"status": "affected",
"version": "2b06cdf3e688b98fcc9945873b5d42792bd4eee0",
"lessThan": "e8686fd8d18b99f3a9038683045b2f2338a7706d",
"versionType": "git"
},
{
"status": "affected",
"version": "2b06cdf3e688b98fcc9945873b5d42792bd4eee0",
"lessThan": "a9340ebdc13f8bb5063c0bc0b037ee7e640d4ae9",
"versionType": "git"
},
{
"status": "affected",
"version": "2b06cdf3e688b98fcc9945873b5d42792bd4eee0",
"lessThan": "f833821e4b52ab6335d443ede5fb79c38e61d19a",
"versionType": "git"
},
{
"status": "affected",
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"lessThan": "f0ab9a71167bae308e05ab13b65e2007504a603f",
"versionType": "git"
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{
"status": "affected",
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"lessThan": "8dd8929b71c4f06c614f8f54c2cc070453faae16",
"versionType": "git"
},
{
"status": "affected",
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"lessThan": "0ea8f06454012d9e7f9c6e6253df710949bf6294",
"versionType": "git"
},
{
"status": "affected",
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"versionType": "git"
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{
"status": "affected",
"version": "2b06cdf3e688b98fcc9945873b5d42792bd4eee0",
"lessThan": "c283e9ada7fcb7dd4b10592623086b2e6d2f9925",
"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"
},
{
"status": "affected",
"version": "3.16.52",
"lessThan": "3.17",
"versionType": "semver"
},
{
"status": "affected",
"version": "4.4.163",
"lessThan": "4.5",
"versionType": "semver"
},
{
"status": "affected",
"version": "3.18.101",
"lessThan": "3.19",
"versionType": "semver"
},
{
"status": "affected",
"version": "4.1.52",
"lessThan": "4.2",
"versionType": "semver"
},
{
"status": "affected",
"version": "4.4.123",
"lessThan": "4.5",
"versionType": "semver"
},
{
"status": "affected",
"version": "4.9.89",
"lessThan": "4.10",
"versionType": "semver"
}
],
"programFiles": [
"net/xfrm/xfrm_state.c"
],
"defaultStatus": "unaffected"
},
{
"repo": "https://git.kernel.org/pub/scm/linux/kernel/git/stable/linux.git",
"vendor": "Linux",
"product": "Linux",
"versions": [
{
"status": "affected",
"version": "4.14"
},
{
"status": "unaffected",
"version": "0",
"lessThan": "4.14",
"versionType": "semver"
},
{
"status": "unaffected",
"version": "5.10.267",
"versionType": "semver",
"lessThanOrEqual": "5.10.*"
},
{
"status": "unaffected",
"version": "5.15.218",
"versionType": "semver",
"lessThanOrEqual": "5.15.*"
},
{
"status": "unaffected",
"version": "6.1.185",
"versionType": "semver",
"lessThanOrEqual": "6.1.*"
},
{
"status": "unaffected",
"version": "6.6.154",
"versionType": "semver",
"lessThanOrEqual": "6.6.*"
},
{
"status": "unaffected",
"version": "6.12.106",
"versionType": "semver",
"lessThanOrEqual": "6.12.*"
},
{
"status": "unaffected",
"version": "6.18.47",
"versionType": "semver",
"lessThanOrEqual": "6.18.*"
},
{
"status": "unaffected",
"version": "7.1.6",
"versionType": "semver",
"lessThanOrEqual": "7.1.*"
},
{
"status": "unaffected",
"version": "7.2",
"versionType": "original_commit_for_fix",
"lessThanOrEqual": "*"
}
],
"programFiles": [
"net/xfrm/xfrm_state.c"
],
"defaultStatus": "affected"
}
]- Related CVEs
- CVE-2026-64581
Source reference:
/cveMetadata/cveId
Publisher severity
high
Source reference: /containers/cna/metrics
- Event
- #41098 · Revision 1
- Added to Heist Feed
- Publisher date