CVE-2025-40231 Affecting kernel-source-azure package, versions <6.4.0-150700.20.24.1


Severity

Recommended
0.0
medium
0
10

Based on SUSE Linux Enterprise Server security rating.

Threat Intelligence

EPSS
0.05% (17th percentile)

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  • Snyk IDSNYK-SLES157-KERNELSOURCEAZURE-15106599
  • published27 Jan 2026
  • disclosed23 Jan 2026

Introduced: 23 Jan 2026

CVE-2025-40231  (opens in a new tab)

How to fix?

Upgrade SLES:15.7 kernel-source-azure to version 6.4.0-150700.20.24.1 or higher.

NVD Description

Note: Versions mentioned in the description apply only to the upstream kernel-source-azure package and not the kernel-source-azure package as distributed by SLES. See How to fix? for SLES:15.7 relevant fixed versions and status.

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().

CVSS Base Scores

version 3.1