🛡️ CVE-2025-39994 — kernel

🟠 CVSS 7.3 — High ✅ No Known Exploit NVD
7.3
CVSS Score
0 Low4 Medium7 High9 Critical10

Description

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

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]

How this vulnerability can be exploited

This issue can be reached with local access to the system, attack complexity is low, an attacker needs low-level privileges on the target. A user must be tricked into taking some action. The scope is unchanged, so the impact stays within the vulnerable component. Rated impact: confidentiality high, integrity high, availability high.

Affected software

CVE-2025-39994 is recorded against 2 packages.

  • kernel (from 6.17.0 up to 6.17.1)
  • unknown

Timeline and source

Published on 15 October 2025 and last revised on 6 August 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)
git.kernel.org (Web)
git.kernel.org (Web)
github.com (Advisory)
nvd.nist.gov (Advisory)
git.kernel.org (Package)

CVE-2025-39994 on other distributions

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

Details

Severity High
CVSS Score 7.3
CVSS Vector CVSS:3.1/AV:L/AC:L/PR:L/UI:R/S:U/C:H/I:H/A:H
CWE N/A
Public Exploit ✅ No
Source NVD
Published 2025-10-15
Updated 2026-08-12
Modified 2026-08-06
Fix URL N/A

Affected Packages

Software From version Fixed in
kernel 6.17.0 6.17.1
unknown — —

References

Similar Threats

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