Critical ALSA Timer Vulnerability in Linux Package: Deadlock Risk Due to Mutex Mismanagement
Summary
DEBIAN-CVE-2025-23134: In the Linux kernel, the following vulnerability has been resolved: ALSA: timer: Don't take register_mutex with copy_from/to_user() The infamous mmap_lock taken in copy_from/to_user() can be often problematic when it's c... Affects linux versions < 6.12.25-1. Fixed in 6.12.25-1. How to fix ↓
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Background
The Linux kernel is a core component of the Debian operating system, providing essential services and managing hardware resources. It is known for its stability, performance, and extensive support for various hardware architectures. However, like any complex software, it is susceptible to vulnerabilities that can impact system security and reliability. This specific vulnerability affects the ALSA (Advanced Linux Sound Architecture) timer code, which is responsible for managing audio timing and playback in Linux systems.
Vulnerability Detail
In the Linux kernel, a vulnerability has been identified in the ALSA timer code where the register_mutex is incorrectly held during the execution of copy_from/to_user() functions. This can lead to potential deadlocks when the mmap_lock is taken within another mutex. The issue arose during a code conversion to use guard() for mutex management, which inadvertently introduced this problematic pattern. If exploited, this vulnerability could disrupt audio services and lead to system instability.
How To Fix
Minimum fixed version
6.12.25-1
This is the first release that contains the fix.
sudo apt-get install --only-upgrade linuxTip — Not sure which version your app runs? Vulert can match this fix to it. Scan free →
Workaround
Currently, there are no specific workarounds mentioned for this vulnerability. It is recommended to apply the patch as soon as it becomes available to mitigate any risks associated with this issue.
Conclusion
The ALSA timer vulnerability in the Linux kernel poses a significant risk due to potential deadlocks caused by improper mutex management. Users are urged to update their Linux package to the latest patched version to ensure system stability and security. Regular monitoring for vulnerabilities using tools like Vulert can help maintain a secure software environment.
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FAQ
The vulnerability involves improper mutex management in the ALSA timer code, which can lead to deadlocks.
You can use the Vulert playground at Vulert Scanner to check if your application is affected by this vulnerability without any signup.
If exploited, this vulnerability could cause audio service disruptions and system instability.
Yes, a patch is available in version 6.12.25-1 of the Linux package.
While there are no specific workarounds, it is crucial to monitor the situation and apply the patch as soon as possible.
References
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