CVE-2026-64581
xfrm: fix sk_dst_cache double-free in xfrm_user_policy()
Description
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 cleared and released with a single xchg(): whichever side wins releases the dst once, the other sees NULL and does nothing. Behaviour is otherwise unchanged.
INFO
Published Date :
Aug. 5, 2026, 8:16 a.m.
Last Modified :
Aug. 27, 2026, 1:18 p.m.
Remotely Exploit :
No
Source :
416baaa9-dc9f-4396-8d5f-8c081fb06d67
CVSS Scores
| Score | Version | Severity | Vector | Exploitability Score | Impact Score | Source |
|---|---|---|---|---|---|---|
| CVSS 3.1 | HIGH | 416baaa9-dc9f-4396-8d5f-8c081fb06d67 |
Solution
- Apply the kernel patch that uses atomic sk_dst_reset().
- Ensure socket destination cache operations are atomic.
- Verify that dst_release is called only once.
References to Advisories, Solutions, and Tools
Here, you will find a curated list of external links that provide in-depth
information, practical solutions, and valuable tools related to
CVE-2026-64581.
CWE - Common Weakness Enumeration
While CVE identifies
specific instances of vulnerabilities, CWE categorizes the common flaws or
weaknesses that can lead to vulnerabilities. CVE-2026-64581 is
associated with the following CWEs:
Common Attack Pattern Enumeration and Classification (CAPEC)
Common Attack Pattern Enumeration and Classification
(CAPEC)
stores attack patterns, which are descriptions of the common attributes and
approaches employed by adversaries to exploit the CVE-2026-64581
weaknesses.
We scan GitHub repositories to detect new proof-of-concept exploits. Following list is a collection of public exploits and proof-of-concepts, which have been published on GitHub (sorted by the most recently updated).
Results are limited to the first 15 repositories due to potential performance issues.
The following list is the news that have been mention
CVE-2026-64581 vulnerability anywhere in the article.
The following table lists the changes that have been made to the
CVE-2026-64581 vulnerability over time.
Vulnerability history details can be useful for understanding the evolution of a vulnerability, and for identifying the most recent changes that may impact the vulnerability's severity, exploitability, or other characteristics.
-
CVE Modified by 416baaa9-dc9f-4396-8d5f-8c081fb06d67
Aug. 27, 2026
Action Type Old Value New Value Added Affected Affected value modified. <a href="https://github.com/CVEProject/cvelistV5/blob/main/cves/2026/64xxx/CVE-2026-64581.json">CVE-2026-64581</a> Added Reference https://git.kernel.org/stable/c/0ea8f06454012d9e7f9c6e6253df710949bf6294 Added Reference https://git.kernel.org/stable/c/8dd8929b71c4f06c614f8f54c2cc070453faae16 Added Reference https://git.kernel.org/stable/c/96b678d08268b5f5c6fc99d4289d9b7e334fc683 Added Reference https://git.kernel.org/stable/c/a9340ebdc13f8bb5063c0bc0b037ee7e640d4ae9 Added Reference https://git.kernel.org/stable/c/c283e9ada7fcb7dd4b10592623086b2e6d2f9925 Added Reference https://git.kernel.org/stable/c/e8686fd8d18b99f3a9038683045b2f2338a7706d Added Reference https://git.kernel.org/stable/c/f0ab9a71167bae308e05ab13b65e2007504a603f Added Reference https://git.kernel.org/stable/c/f833821e4b52ab6335d443ede5fb79c38e61d19a Removed Reference https://git.kernel.org/stable/c/96b678d08268b5f5c6fc99d4289d9b7e334fc683 Removed Reference https://git.kernel.org/stable/c/c283e9ada7fcb7dd4b10592623086b2e6d2f9925 -
CVE Modified by 416baaa9-dc9f-4396-8d5f-8c081fb06d67
Aug. 17, 2026
Action Type Old Value New Value Changed Affected [{'repo': 'https://git.kernel.org/pub/scm/linux/kernel/git/stable/linux.git', 'vendor': 'Linux', 'product': 'Linux', 'versions': [{'status': 'affected', 'version': '2b06cdf3e688b98fcc9945873b5d42792bd4eee0', 'lessThan': '96b678d08268b5f5c6fc99d4289d9b7e334fc683', 'versionType': 'git'}, {'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': '7.1.6', 'versionType': 'semver', 'lessThanOrEqual': '7.1.*'}, {'status': 'unaffected', 'version': '7.2-rc4', 'versionType': 'original_commit_for_fix', 'lessThanOrEqual': '*'}], 'programFiles': ['net/xfrm/xfrm_state.c'], 'defaultStatus': 'affected'}] [{'repo': 'https://git.kernel.org/pub/scm/linux/kernel/git/stable/linux.git', 'vendor': 'Linux', 'product': 'Linux', 'versions': [{'status': 'affected', 'version': '2b06cdf3e688b98fcc9945873b5d42792bd4eee0', 'lessThan': '96b678d08268b5f5c6fc99d4289d9b7e334fc683', 'versionType': 'git'}, {'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': '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'}] -
CVE Modified by 416baaa9-dc9f-4396-8d5f-8c081fb06d67
Aug. 08, 2026
Action Type Old Value New Value Added CVSS V3.1 AV:L/AC:L/PR:L/UI:N/S:U/C:H/I:H/A:H -
New CVE Received by 416baaa9-dc9f-4396-8d5f-8c081fb06d67
Aug. 05, 2026
Action Type Old Value New Value Added Affected [{'repo': 'https://git.kernel.org/pub/scm/linux/kernel/git/stable/linux.git', 'vendor': 'Linux', 'product': 'Linux', 'versions': [{'status': 'affected', 'version': '2b06cdf3e688b98fcc9945873b5d42792bd4eee0', 'lessThan': '96b678d08268b5f5c6fc99d4289d9b7e334fc683', 'versionType': 'git'}, {'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': '7.1.6', 'versionType': 'semver', 'lessThanOrEqual': '7.1.*'}, {'status': 'unaffected', 'version': '7.2-rc4', 'versionType': 'original_commit_for_fix', 'lessThanOrEqual': '*'}], 'programFiles': ['net/xfrm/xfrm_state.c'], 'defaultStatus': 'affected'}] Added Description 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 cleared and released with a single xchg(): whichever side wins releases the dst once, the other sees NULL and does nothing. Behaviour is otherwise unchanged. Added Reference https://git.kernel.org/stable/c/96b678d08268b5f5c6fc99d4289d9b7e334fc683 Added Reference https://git.kernel.org/stable/c/c283e9ada7fcb7dd4b10592623086b2e6d2f9925