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Double FreeWeakness · CWE-415

CVE-2026-56109

MEDIUM · 6.8 CVSS v3.1 Published 2026-06-22
Patch available
A vendor patch is available. No clean upgrade release — apply the published patch.
See remediation →
73/100
Remediation priority · Elevated
No privileges Zero-click Patch available

Official description Straight from the sourceThe vendor's or NVD's own wording, published unedited. Authoritative, but often terse — it says what broke, rarely what to do.

NVD · unedited
The Advanced Linux Sound Architecture (ALSA) library before 1.2.16.1 contains a double-free vulnerability in parse_def() in src/conf.c that 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.

Technical summary Written by usOur analysis, written from the advisory, the CVSS vector and the affected-version data. It adds context the advisory leaves out, and never invents facts that are not in the source.

dbcve analysis
How this class of weakness works · CWE-415

The same block of memory is freed twice, corrupting the allocator's bookkeeping in ways an attacker can shape toward code execution. It usually stems from tangled ownership of a pointer. The fix is clear, single ownership of each allocation and clearing pointers once they are freed.

General guidance for the double free class — the official description and references above are authoritative for this specific CVE. Want a bespoke review and a reviewed fix? Ask our team →

CVSS breakdown How the score is builtThe industry scoring standard. It rates how the flaw is reached, what it takes to exploit, and what an attacker gains — the score is derived from those, not the other way round.

From the vector
Attack vector
Local
Complexity
Low
Privileges
None
User interaction
None
Scope
Unchanged
Confidentiality
None
Integrity
Low
Availability
High

CVSS:3.1/AV:L/AC:L/PR:N/UI:N/S:U/C:N/I:L/A:H

Remediation Closing itWhat it takes to close this. Where a vendor fix exists we point at it; where none exists we say so plainly, and can build one. Effort estimates are scoped from the advisory, not from your codebase.

dbcve · scoped
Patch available Apply the vendor patch
Vendor patch github.com →
Recommended fix High confidence

Upgrade to alsa-lib version 1.2.16.1 or later

  1. 1. Identify the current version of alsa-lib installed on the system using the package manager or by checking the library version.
  2. 2. Upgrade alsa-lib to version 1.2.16.1 or later, which contains the fix for the double-free vulnerability in parse_def().
  3. 3. On Debian/Ubuntu-based systems, run: sudo apt-get update && sudo apt-get install libasound2 (or libasound2-dev for development libraries).
  4. 4. On Red Hat/CentOS-based systems, run: sudo yum update alsa-lib or sudo dnf update alsa-lib.
  5. 5. For source-based installations, download alsa-lib version 1.2.16.1 or later from the official ALSA project repository and rebuild.
  6. 6. After upgrading, restart any applications that use ALSA to ensure they load the updated library.
  7. 7. Verify the fix by checking the library version matches or exceeds 1.2.16.1.

Generated from the published advisory — verify against the referenced sources before acting.

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References Go to the primary sourcePrimary sources — vendor advisories, patches and trackers. Where our summary and a reference disagree, the reference wins.

Primary sources

Practitioner notes

Contributed

Peer-ranked notes from engineers who’ve handled CVE-2026-56109 in production — separate from our analysis above.

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What this is

A place for practitioners to share what actually worked: a mitigation you’ve tested, a configuration change, a version- or environment-specific caveat, or a link to a verified patch. The most useful notes rise to the top as peers upvote them, so the signal stays high.

What belongs here
  • Verified mitigations, workarounds, and config changes
  • Version or environment caveats, and links to real fixes
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