ALSA: pcm: oss: Limit the period size to 16MB

Kernel Updated 02 Oct 2025

Summary

19/12/2021

Disclosed on

N/A

Severity

No i

Fix available

Unrated

Severity

Not published

CVSS Score

GSD-2021-1002597: ALSA: pcm: oss: Limit the period size to 16MB. Affects Kernel versions < 35a3e511032146941085f87dd9fb5b82ea5c00a2. No fix is published. How to fix ↓

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Background

The ALSA (Advanced Linux Sound Architecture) package is responsible for providing audio and MIDI functionality to the Linux operating system. It is a software framework that enables sound card drivers and sound servers to communicate with the audio hardware. ALSA supports various audio interfaces and provides APIs for audio playback, recording, and mixing. The vulnerability in question affects the ALSA pcm oss module, which is responsible for providing compatibility with the OSS (Open Sound System) API. This module allows applications that rely on the OSS API to work with ALSA. However, a flaw in the module's implementation allows the period size to exceed 16MB, potentially leading to memory corruption or other security issues.

Vulnerability Detail

The vulnerability arises from a lack of proper validation and limitation of the period size in the ALSA pcm oss module. By exceeding the maximum allowed period size of 16MB, an attacker could exploit this flaw to trigger memory corruption or other security vulnerabilities. The exact impact and attack vectors have not been proven yet, but the potential for exploitation exists. It is important to note that this vulnerability has been addressed in the Linux Kernel version v5.15.8 by commit 35a3e511032146941085f87dd9fb5b82ea5c00a2.

How To Fix

No fixed version is published for this vulnerability.

To fix this vulnerability, it is recommended to update the Linux Kernel to version v5.15.8 or later. This update includes the necessary patch to limit the period size to 16MB in the ALSA pcm oss module. Users can obtain the updated kernel from the official Linux Kernel repository or through their respective Linux distribution's package management system. It is crucial to keep the system up to date with the latest security patches to mitigate the risk of exploitation.

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Workaround

As this vulnerability has been fixed in the Linux Kernel, there is no specific workaround available. Users are advised to update their kernel to the patched version.

Conclusion

The ALSA pcm oss module in the Linux Kernel was found to have a vulnerability that allowed the period size to exceed 16MB, potentially leading to memory corruption or other security issues. This vulnerability has been addressed in the Linux Kernel version v5.15.8 by commit 35a3e511032146941085f87dd9fb5b82ea5c00a2. Users are advised to update their kernel to the patched version to mitigate the risk of exploitation. For further support on vulnerability remediation, please contact DevNack.com.

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