Critical Vulnerability in Linux Kernel: ALSA Seq Port-Info Ioctl Serialization Flaw
Summary
DEBIAN-CVE-2026-98742: In the Linux kernel, the following vulnerability has been resolved: ALSA: seq: Serialize compat port-info ioctls The native sequencer ioctl path serializes handler calls with client->ioctl_mutex, but the translated port-... Affects linux versions 6.1.106-1 – 7.3~rc7-1~exp1. No fix is published. How to fix ↓
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Background
The Linux kernel is the core component of many operating systems, responsible for managing hardware and system resources. It provides essential services for all other parts of the operating system. The ALSA (Advanced Linux Sound Architecture) subsystem is integral for sound card drivers and audio processing. This vulnerability affects the ALSA sequencer, which handles MIDI and audio sequencing, potentially leading to serious security issues.
Vulnerability Detail
In the Linux kernel, a vulnerability has been identified in the ALSA sequencer where the compat port-info ioctls are not properly serialized. The native sequencer ioctl path uses a mutex to serialize handler calls, while the compat path does not, allowing concurrent CREATE_PORT requests to bypass the port-count check. This can lead to an integer port index exceeding the address field range, causing a wrap-around to an existing index. As a result, subsequent subscriber teardown may resolve the duplicate address to the wrong port, leading to access of a freed subscriber and potential system instability or exploitation.
How To Fix
No fixed version is published for this vulnerability.
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Workaround
Currently, there are no specific workarounds mentioned for this vulnerability other than applying the patch. It is recommended to monitor the system for any unusual behavior until the patch can be applied.
Conclusion
The ALSA sequencer vulnerability in the Linux kernel poses significant risks due to improper serialization of ioctl calls. It is crucial to apply the available patches to mitigate these risks and ensure system stability. Regular monitoring and updates are essential for maintaining security.
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FAQ
The vulnerability can lead to system instability and potential exploitation by allowing unauthorized access to freed memory.
You can use tools like Vulert to monitor and alert for open-source vulnerabilities in your software. Visit Vulert Scanner to check if your application is affected.
Yes, the vulnerability affects specific versions of the Linux kernel in Debian 12, 13, and 14.
While there are no specific workarounds, it is advisable to monitor your system closely for any unusual activity until you can apply the patch.
Detailed information can be found in the official Debian security advisories and vulnerability databases.
References
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