CVE-2026-56109 alsa-project CVE debrief

Who should care

This vulnerability affects users of the ALSA library, particularly those using Linux systems with sound capabilities. Developers and maintainers of Linux distributions, as well as users of ALSA-based applications, should be aware of this vulnerability and take steps to mitigate it. Given the high severity of this vulnerability, users should prioritize patching or upgrading to a version of ALSA library that is not vulnerable.

Technical summary

The double-free vulnerability in ALSA library's parse_def() function can be exploited by providing malicious ALSA configuration text. This can lead to memory corruption, potentially allowing attackers to execute arbitrary code or cause a denial of service. The vulnerability is caused by the function's failure to check return values before continuing, resulting in snd_config_delete() being called twice on the same already-freed node. This can result in a NULL-pointer write or invalid memory read. The CVSS vector for this vulnerability is CVSS:4.0/AV:L/AC:L/AT:N/PR:N/UI:N/VC:N/VI:L/VA:H/SC:N/SI:N/SA:N/E:X/CR:X/IR:X/AR:X/MAV:X/MAC:X/MAT:X/MPR:X/MUI:X/MVC:X/MVI:X/MVA:X/MSC:X/MSI:X/MSA:X/S:X/AU:X/R:X/V:X/RE:X/U:X.

Defensive priority

High priority should be given to patching or upgrading to a version of ALSA library that is not vulnerable. Users should ensure that their Linux systems and ALSA-based applications are updated to use a version of ALSA library that is not vulnerable to this double-free vulnerability.

Recommended defensive actions

• Patch or upgrade to ALSA library version 1.2.16.1 or later
• Review and update Linux system and ALSA-based application configurations to ensure use of patched ALSA library
• Monitor system and application logs for potential exploitation attempts
• Consider implementing compensating controls, such as memory protection mechanisms
• Perform thorough inventory checks to identify potentially affected systems and applications

Evidence notes

The CVE record for CVE-2026-56109 was obtained from the official CVE website. The vulnerability details were obtained from the NVD database and various source references, including GitHub commits and release notes. The CVSS score and vector were obtained from the NVD database.

Sources and references

Methodology and review provenance

AI-assisted synthesis based on stored public vulnerability evidence. System validation, approval state, and publication status do not by themselves establish human review of this revision. PatchSiren helps prioritize defensive review and does not prove exposure or remediation on any system.