CVE-2021-29951

Description

The Mozilla Maintenance Service granted SERVICE_START access to BUILTIN|Users which, in a domain network, grants normal remote users access to start or stop the service. This could be used to prevent the browser update service from operating (if an attacker spammed the 'Stop' command); but also exposed attack surface in the maintenance service. *Note: This issue only affected Windows operating systems older than Win 10 build 1709. Other operating systems are unaffected.*. This vulnerability affects Thunderbird < 78.10.1, Firefox < 87, and Firefox ESR < 78.10.1.

Category

6.5
CVSS
Severity: Medium
CVSS 3.1 •
CVSS 2.0 •
EPSS 0.47%
Vendor Advisory mozilla.org Vendor Advisory mozilla.org Vendor Advisory mozilla.org Vendor Advisory mozilla.org
Affected: Mozilla Thunderbird
Affected: Mozilla Firefox
Affected: Mozilla Firefox ESR
Published at:
Updated at:

References

Frequently Asked Questions

What is the severity of CVE-2021-29951?
CVE-2021-29951 has been scored as a medium severity vulnerability.
How to fix CVE-2021-29951?
To fix CVE-2021-29951, make sure you are using an up-to-date version of the affected component(s) by checking the vendor release notes. As for now, there are no other specific guidelines available.
Is CVE-2021-29951 being actively exploited in the wild?
As for now, there are no information to confirm that CVE-2021-29951 is being actively exploited. According to its EPSS score, there is a ~0% probability that this vulnerability will be exploited by malicious actors in the next 30 days.
What software or system is affected by CVE-2021-29951?
CVE-2021-29951 affects Mozilla Thunderbird, Mozilla Firefox, Mozilla Firefox ESR.
This platform uses data from the NIST NVD, MITRE CVE, MITRE CWE, First.org and CISA KEV but is not endorsed or certified by these entities. CVE is a registred trademark of the MITRE Corporation and the authoritative source of CVE content is MITRE's CVE web site. CWE is a registred trademark of the MITRE Corporation and the authoritative source of CWE content is MITRE's CWE web site.
© 2025 Under My Watch. All Rights Reserved.