ALSA Project alsa-lib up to 1.2.15.2 Topology File tplg_decode_control_mixer1 num_channels array index

Summaryinfo

A vulnerability, which was classified as problematic, has been found in ALSA Project alsa-lib up to 1.2.15.2. This issue affects the function tplg_decode_control_mixer1 of the component Topology File Handler. This manipulation of the argument num_channels causes array index. This vulnerability is registered as CVE-2026-25068. Remote exploitation of the attack is possible. No exploit is available. To fix this issue, it is recommended to deploy a patch.

Detailsinfo

A vulnerability has been found in ALSA Project alsa-lib up to 1.2.15.2 and classified as problematic. Affected by this vulnerability is the function tplg_decode_control_mixer1 of the component Topology File Handler. The manipulation of the argument num_channels with an unknown input leads to a array index vulnerability. The CWE definition for the vulnerability is CWE-129. The product uses untrusted input when calculating or using an array index, but the product does not validate or incorrectly validates the index to ensure the index references a valid position within the array. As an impact it is known to affect availability. The summary by CVE is:

alsa-lib versions 1.2.2 up to and including 1.2.15.2, prior to commit 5f7fe33, contain a heap-based buffer overflow in the topology mixer control decoder. The tplg_decode_control_mixer1() function reads the num_channels field from untrusted .tplg data and uses it as a loop bound without validating it against the fixed-size channel array (SND_TPLG_MAX_CHAN). A crafted topology file with an excessive num_channels value can cause out-of-bounds heap writes, leading to a crash.

The weakness was published by Sajeeb Lohani as 5f7fe33002d2d98d84f72e381ec2cccc0d5d3d40. It is possible to read the advisory at github.com. This vulnerability is known as CVE-2026-25068 since 01/28/2026. The exploitation appears to be easy. The attack can be launched remotely. The exploitation doesn't need any form of authentication. It demands that the victim is doing some kind of user interaction. Technical details of the vulnerability are known, but there is no available exploit.

The vulnerability scanner Nessus provides a plugin with the ID 297176 (Linux Distros Unpatched Vulnerability : CVE-2026-25068), which helps to determine the existence of the flaw in a target environment.

Applying the patch 5f7fe33002d2d98d84f72e381ec2cccc0d5d3d40 is able to eliminate this problem. The bugfix is ready for download at github.com.

The vulnerability is also documented in the databases at Tenable (297176) and EUVD (EUVD-2026-4970). Statistical analysis made it clear that VulDB provides the best quality for vulnerability data.

Productinfo

Type

• Project Management Software

Vendor

• ALSA Project

Name

• alsa-lib

Version

• 1.2.15.0
• 1.2.15.1
• 1.2.15.2

License

• open-source

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CPE 2.2info

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Statistical analysis made it clear that VulDB provides the best quality for vulnerability data.

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