CVE-2025-39994 Affecting kernel-syms package, versions <6.4.0-150600.23.78.1


Severity

Recommended
0.0
medium
0
10

Based on SUSE Linux Enterprise Server security rating.

Threat Intelligence

EPSS
0.05% (15th percentile)

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  • Snyk IDSNYK-SLES156-KERNELSYMS-14071763
  • published20 Nov 2025
  • disclosed19 Nov 2025

Introduced: 19 Nov 2025

NewCVE-2025-39994  (opens in a new tab)

How to fix?

Upgrade SLES:15.6 kernel-syms to version 6.4.0-150600.23.78.1 or higher.

NVD Description

Note: Versions mentioned in the description apply only to the upstream kernel-syms package and not the kernel-syms package as distributed by SLES. See How to fix? for SLES:15.6 relevant fixed versions and status.

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

media: tuner: xc5000: Fix use-after-free in xc5000_release

The original code uses cancel_delayed_work() in xc5000_release(), which does not guarantee that the delayed work item timer_sleep has fully completed if it was already running. This leads to use-after-free scenarios where xc5000_release() may free the xc5000_priv while timer_sleep is still active and attempts to dereference the xc5000_priv.

A typical race condition is illustrated below:

CPU 0 (release thread) | CPU 1 (delayed work callback) xc5000_release() | xc5000_do_timer_sleep() cancel_delayed_work() | hybrid_tuner_release_state(priv) | kfree(priv) | | priv = container_of() // UAF

Replace cancel_delayed_work() with cancel_delayed_work_sync() to ensure that the timer_sleep is properly canceled before the xc5000_priv memory is deallocated.

A deadlock concern was considered: xc5000_release() is called in a process context and is not holding any locks that the timer_sleep work item might also need. Therefore, the use of the _sync() variant is safe here.

This bug was initially identified through static analysis.

[hverkuil: fix typo in Subject: tunner -> tuner]

CVSS Base Scores

version 3.1