CVE-2026-68137
net/x25: fix use-after-free in x25_kill_by_neigh()
Description
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().
INFO
Published Date :
Aug. 10, 2026, 1:19 p.m.
Last Modified :
Aug. 13, 2026, 11:17 p.m.
Remotely Exploit :
Yes !
Source :
416baaa9-dc9f-4396-8d5f-8c081fb06d67
CVSS Scores
| Score | Version | Severity | Vector | Exploitability Score | Impact Score | Source |
|---|---|---|---|---|---|---|
| CVSS 3.1 | CRITICAL | 416baaa9-dc9f-4396-8d5f-8c081fb06d67 |
Solution
- Update the Linux kernel to the resolved version.
- Rebuild and deploy the kernel.
- Restart affected systems.
References to Advisories, Solutions, and Tools
Here, you will find a curated list of external links that provide in-depth
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CVE-2026-68137.
CWE - Common Weakness Enumeration
While CVE identifies
specific instances of vulnerabilities, CWE categorizes the common flaws or
weaknesses that can lead to vulnerabilities. CVE-2026-68137 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-2026-68137
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).
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The following list is the news that have been mention
CVE-2026-68137 vulnerability anywhere in the article.
The following table lists the changes that have been made to the
CVE-2026-68137 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. 13, 2026
Action Type Old Value New Value Added CVSS V3.1 AV:N/AC:L/PR:N/UI:N/S:U/C:H/I:H/A:H -
New CVE Received by 416baaa9-dc9f-4396-8d5f-8c081fb06d67
Aug. 10, 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': '7781607938c8371d4c2b243527430241c62e39c2', 'lessThan': '3f4fe26c20c30bd5a2e2583e80685def0b27858c', 'versionType': 'git'}, {'status': 'affected', 'version': '7781607938c8371d4c2b243527430241c62e39c2', 'lessThan': '610678d4be94b619c751572e8a58de705592cd07', 'versionType': 'git'}, {'status': 'affected', 'version': '7781607938c8371d4c2b243527430241c62e39c2', 'lessThan': 'ec6d91a1bf2ebd767d3d43f6d249ee0ed3f4558a', 'versionType': 'git'}, {'status': 'affected', 'version': '7781607938c8371d4c2b243527430241c62e39c2', 'lessThan': '9aabda553184346f74810e2ee1d96920b4612e3f', 'versionType': 'git'}, {'status': 'affected', 'version': '7781607938c8371d4c2b243527430241c62e39c2', 'lessThan': '5499e0602d2faafd42c580d25f615903c3fbe11b', 'versionType': 'git'}, {'status': 'affected', 'version': 'dffc859d1d9560da594e4282091781b8d2715f00', 'versionType': 'git'}, {'status': 'affected', 'version': '858642789ada1b48630f322e59416ca9fca3e6b7', 'versionType': 'git'}, {'status': 'affected', 'version': '4c240c5a105557e4546d0836e694868f22fd09b0', 'versionType': 'git'}, {'status': 'affected', 'version': '9acf05b4e7b55fdb712ef7b331dbce5bcd391d0f', 'versionType': 'git'}, {'status': 'affected', 'version': '5c94b6205e87411dbe9dc1ca088eb36b8837fb47', 'versionType': 'git'}, {'status': 'affected', 'version': '409570a619c1cda2e0fde6018a256b9e3d3ba0ee', 'versionType': 'git'}, {'status': 'affected', 'version': '4a279d7ee1c65411b4055ecd428b8aa2b1711c1f', 'versionType': 'git'}, {'status': 'affected', 'version': '671529db75e6be777bb1c76aa07c2bdd2992be6d', 'versionType': 'git'}, {'status': 'affected', 'version': '4.9.311', 'lessThan': '4.10', 'versionType': 'semver'}, {'status': 'affected', 'version': '4.14.276', 'lessThan': '4.15', 'versionType': 'semver'}, {'status': 'affected', 'version': '4.19.238', 'lessThan': '4.20', 'versionType': 'semver'}, {'status': 'affected', 'version': '5.4.189', 'lessThan': '5.5', 'versionType': 'semver'}, {'status': 'affected', 'version': '5.10.110', 'lessThan': '5.11', 'versionType': 'semver'}, {'status': 'affected', 'version': '5.15.33', 'lessThan': '5.16', 'versionType': 'semver'}, {'status': 'affected', 'version': '5.16.19', 'lessThan': '5.17', 'versionType': 'semver'}, {'status': 'affected', 'version': '5.17.2', 'lessThan': '5.18', 'versionType': 'semver'}], 'programFiles': ['net/x25/af_x25.c'], 'defaultStatus': 'unaffected'}, {'repo': 'https://git.kernel.org/pub/scm/linux/kernel/git/stable/linux.git', 'vendor': 'Linux', 'product': 'Linux', 'versions': [{'status': 'affected', 'version': '5.18'}, {'status': 'unaffected', 'version': '0', 'lessThan': '5.18', 'versionType': 'semver'}, {'status': 'unaffected', 'version': '6.6.148', 'versionType': 'semver', 'lessThanOrEqual': '6.6.*'}, {'status': 'unaffected', 'version': '6.12.101', 'versionType': 'semver', 'lessThanOrEqual': '6.12.*'}, {'status': 'unaffected', 'version': '6.18.42', 'versionType': 'semver', 'lessThanOrEqual': '6.18.*'}, {'status': 'unaffected', 'version': '7.1.6', 'versionType': 'semver', 'lessThanOrEqual': '7.1.*'}, {'status': 'unaffected', 'version': '7.2-rc5', 'versionType': 'original_commit_for_fix', 'lessThanOrEqual': '*'}], 'programFiles': ['net/x25/af_x25.c'], 'defaultStatus': 'affected'}] Added Description 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(). Added Reference https://git.kernel.org/stable/c/3f4fe26c20c30bd5a2e2583e80685def0b27858c Added Reference https://git.kernel.org/stable/c/5499e0602d2faafd42c580d25f615903c3fbe11b Added Reference https://git.kernel.org/stable/c/610678d4be94b619c751572e8a58de705592cd07 Added Reference https://git.kernel.org/stable/c/9aabda553184346f74810e2ee1d96920b4612e3f Added Reference https://git.kernel.org/stable/c/ec6d91a1bf2ebd767d3d43f6d249ee0ed3f4558a