PatchSiren cyber security CVE debrief
CVE-2026-56109 alsa-project CVE debrief
The Advanced Linux Sound Architecture (ALSA) library before version 1.2.16.1 contains a double-free vulnerability in the parse_def() function in src/conf.c. This vulnerability allows attackers to corrupt memory by supplying maliciously crafted ALSA configuration text. When parsing nested compound or array configuration blocks, parse_def() fails to check return values before continuing, causing snd_config_delete() to be called twice on the same already-freed node, resulting in a NULL-pointer write or invalid memory read. The Common Vulnerability Scoring System (CVSS) score for this vulnerability is 7, indicating a high severity. The vulnerability was published on June 22, 2026, and last modified on June 23, 2026.
- Vendor
- alsa-project
- Product
- alsa-lib
- CVSS
- HIGH 7
- CISA KEV
- Not listed in stored evidence
- Original CVE published
- 2026-06-22
- Original CVE updated
- 2026-06-23
- Advisory published
- 2026-06-22
- Advisory updated
- 2026-06-23
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.
Official resources
This article is AI-assisted and based on the supplied source corpus.