CVE-2026-68137

Critical

In the Linux kernel, the following vulnerability has been resolved: net/x25: fix use-after-free in x25_kill_by_neigh() x25_kill_by_neigh() walks the global X.25 socket list looking for sockets attached to a terminating neighbour. x25_list_lock protects list membership while the lookup is in progress, but it does not pin a socket's lifetime after the lock is dropped. The function currently drops x25_list_lock before calling lock_sock(s). A concurrent close can run x25_release(), remove the same socket from x25_list, and drop the last socket reference in that window. The neighbour teardown path can then lock or inspect a freed struct sock/struct x25_sock. Take sock_hold(s) while x25_list_lock still proves that the list entry is live, then drop the temporary reference after the socket has been locked, rechecked, and released. Recheck x25_sk(s)->neighbour after lock_sock(), because another path may have disconnected the socket before this path acquired the socket lock. Restart the list walk after each disconnect because the list lock was dropped and the previous iterator state may no longer be valid. A QEMU/KASAN run against origin/master reproduced a slab-use-after-free in x25_kill_by_neigh().

Package Linux Kernel
Published 2026-08-10
Last modified 2026-08-19
CVSS version 3.1
Patch available
Yes

CVSS 3.1 score

9.8

out of 10
Critical
Attack Vector
Network
Attack Complexity
Low
Privileges Required
None
User Interaction
None
Scope
Unchanged
Confidentiality
High
Integrity
High
Availability
High
Vector string
CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:H/I:H/A:H

Affected versions

Linux kernel versions 5.10.110, 5.15.33, 4.9.311, 4.14.276, 4.19.238, 5.4.189, 5.16.19, 5.17.2, 5.18 and later are affected. Fixed in 5.10.265, 5.15.216, 6.1.183, 6.6.148, 6.12.101, 6.18.42, 7.1.6, 7.2 and their respective stable series.

Affected from
≥ 5.10.110 ≥ 5.15.33 ≥ 4.9.311 ≥ 4.14.276 ≥ 4.19.238 ≥ 5.4.189 ≥ 5.16.19 ≥ 5.17.2 ≥ 5.18
Fixed in
✓ 5.10.265 5.10.x ✓ 5.15.216 5.15.x ✓ 6.1.183 6.1.x ✓ 6.6.148 6.6.x ✓ 6.12.101 6.12.x ✓ 6.18.42 6.18.x ✓ 7.1.6 7.1.x ✓ 7.2

References

8 total
Showing 5 of 8 references View all on NVD

Frequently asked questions

  • What is CVE-2026-68137?

    CVE-2026-68137 is a Critical severity Linux kernel vulnerability with a CVSS score of 9.8 out of 10 . It affects Linux kernel versions from 5.10.110 onward and has been patched in 5.10.265, 5.15.216, 6.1.183 and others. CVE-2026-68137 has not been confirmed as actively exploited and is not listed in the CISA KEV catalog.

  • What is the CVSS score for CVE-2026-68137?

    CVE-2026-68137 has a CVSS score of 9.8 out of 10, rated Critical severity (CVSS 3.1). The vector string is CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:H/I:H/A:H .

  • Is there a patch available for CVE-2026-68137?

    Yes. CVE-2026-68137 has been patched. Fixed versions include 5.10.265, 5.15.216, 6.1.183 and others. If you are running Linux kernel 5.10.110 or later up to the fix versions, apply the relevant patch for your kernel branch.

  • Is CVE-2026-68137 actively exploited?

    No. CVE-2026-68137 has not been confirmed as actively exploited. It is not listed in the CISA Known Exploited Vulnerabilities (KEV) catalog.

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