CVE-2025-39994
media: tuner: xc5000: Fix use-after-free in xc5000_release
Description
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]
INFO
Published Date :
Oct. 15, 2025, 8:15 a.m.
Last Modified :
Oct. 16, 2025, 3:28 p.m.
Remotely Exploit :
No
Source :
416baaa9-dc9f-4396-8d5f-8c081fb06d67
Solution
- Replace cancel_delayed_work with cancel_delayed_work_sync.
- Ensure timer_sleep completes before memory deallocation.
- Apply provided kernel patches for media tuner driver.
References to Advisories, Solutions, and Tools
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CVE-2025-39994.
CWE - Common Weakness Enumeration
While CVE identifies
specific instances of vulnerabilities, CWE categorizes the common flaws or
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associated with the following CWEs:
Common Attack Pattern Enumeration and Classification (CAPEC)
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approaches employed by adversaries to exploit the CVE-2025-39994
weaknesses.
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CVE Modified by 416baaa9-dc9f-4396-8d5f-8c081fb06d67
Oct. 15, 2025
Action Type Old Value New Value Added Reference https://git.kernel.org/stable/c/df0303b4839520b84d9367c2fad65b13650a4d42 -
New CVE Received by 416baaa9-dc9f-4396-8d5f-8c081fb06d67
Oct. 15, 2025
Action Type Old Value New Value Added Description 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] Added Reference https://git.kernel.org/stable/c/40b7a19f321e65789612ebaca966472055dab48c Added Reference https://git.kernel.org/stable/c/4266f012806fc18e46da4a04d130df59a4946f93 Added Reference https://git.kernel.org/stable/c/71ed8b81a4906cb785966910f39cf7f5ad60a69e Added Reference https://git.kernel.org/stable/c/9a00de20ed8ba90888479749b87bc1532cded4ce Added Reference https://git.kernel.org/stable/c/effb1c19583bca7022fa641a70766de45c6d41ac