🛡️ CVE-2025-40231 — kernel

⚪ Unknown ✅ No Known Exploit NVD
N/A
CVSS Score
0 Low4 Medium7 High9 Critical10

Description

vsock: fix lock inversion in vsock_assign_transport()

In the Linux kernel, the following vulnerability has been resolved:

vsock: fix lock inversion in vsock_assign_transport()

Syzbot reported a potential lock inversion deadlock between

vsock_register_mutex and sk_lock-AF_VSOCK when vsock_linger() is called.

The issue was introduced by commit 687aa0c5581b ("vsock: Fix

transport_* TOCTOU") which added vsock_register_mutex locking in

vsock_assign_transport() around the transport->release() call, that can

call vsock_linger(). vsock_assign_transport() can be called with sk_lock

held. vsock_linger() calls sk_wait_event() that temporarily releases and

re-acquires sk_lock. During this window, if another thread hold

vsock_register_mutex while trying to acquire sk_lock, a circular

dependency is created.

Fix this by releasing vsock_register_mutex before calling

transport->release() and vsock_deassign_transport(). This is safe

because we don't need to hold vsock_register_mutex while releasing the

old transport, and we ensure the new transport won't disappear by

obtaining a module reference first via try_module_get().

Affected software

CVE-2025-40231 is recorded against 2 packages.

  • kernel (from 6.13.0 up to 6.17.6)
  • unknown

Timeline and source

Published on 4 December 2025 and last revised on 15 July 2026. No public exploit is currently recorded for this entry. Record sourced from NVD.

References

git.kernel.org (Web)
git.kernel.org (Web)
git.kernel.org (Web)
git.kernel.org (Web)
git.kernel.org (Web)
git.kernel.org (Web)
git.kernel.org (Web)
github.com (Advisory)
nvd.nist.gov (Advisory)
git.kernel.org (Package)

CVE-2025-40231 on other distributions

Each distribution ships its own build and its own fixed version. Pick the one you run:

Details

Severity Unknown
CVSS Score N/A
CVSS Vector N/A
CWE N/A
Public Exploit ✅ No
Source NVD
Published 2025-12-04
Updated 2026-08-12
Modified 2026-07-15
Fix URL N/A

Affected Packages

Software From version Fixed in
kernel 6.13.0 6.17.6
unknown — —

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