CVE-2019-11736
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.
Does this matter?
High impact if exploited, but EPSS currently rates exploitation as unlikely (0.21%). Schedule it in the normal patch cycle and watch for a rise in EPSS or a public exploit.
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.
- CVSS 3.1
- 7.0 HIGHCVSS:3.1/AV:L/AC:H/PR:L/UI:N/S:U/C:H/I:H/A:H
- EPSS
- 0.21% probability · 11th percentile
- Public exploits
- None in Exploit-DB
- CISA KEV
- Not listed
- Weakness
- CWE-362
- Affected
- mozilla/firefox · mozilla/firefox esr
- Source
- security@mozilla.org
EPSS 0.2% since 27 October 2026; no change recorded yet. Points are recorded when the score first appears and whenever it moves by a percentage point or more.
References
- http://lists.opensuse.org/opensuse-security-announce/2019-10/msg00011.html
- http://lists.opensuse.org/opensuse-security-announce/2019-10/msg00017.html
- https://bugzilla.mozilla.org/show_bug.cgi?id=1551913Issue Tracking, Permissions Required, Vendor Advisory
- https://bugzilla.mozilla.org/show_bug.cgi?id=1552206Issue Tracking, Permissions Required, Vendor Advisory
- https://www.mozilla.org/security/advisories/mfsa2019-25/Vendor Advisory
- https://www.mozilla.org/security/advisories/mfsa2019-26/Vendor Advisory
- http://lists.opensuse.org/opensuse-security-announce/2019-10/msg00011.html
- http://lists.opensuse.org/opensuse-security-announce/2019-10/msg00017.html
- https://bugzilla.mozilla.org/show_bug.cgi?id=1551913Issue Tracking, Permissions Required, Vendor Advisory
- https://bugzilla.mozilla.org/show_bug.cgi?id=1552206Issue Tracking, Permissions Required, Vendor Advisory
- https://www.mozilla.org/security/advisories/mfsa2019-25/Vendor Advisory
- https://www.mozilla.org/security/advisories/mfsa2019-26/Vendor Advisory
Source: NVD record, EPSS from FIRST.org, KEV from CISA, exploits from Exploit-DB. Refreshed daily. Download this record as JSON.