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Vulnerability · Published Jun 24, 2021 · Assigned by mozilla

CVE-2021-29951

Medium 6.5

In plain English

A medium-severity security flaw in Firefox from Mozilla. There are no confirmed reports of exploitation so far. The chance it is exploited in the next 30 days is estimated at 1.9% (higher than 79% of all known vulnerabilities). Fixed versions are available - upgrade the affected package.

Severity (CVSS NVD)6.5Medium
Exploit odds (30 days)1.9%top 20.8% of all CVEs
Exploited in the wildNo reportsnot in CISA KEV
Attack toolingNoneno public tooling known

Official 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.

Affected packages & fixed versions

EcosystemPackageFixed inAdvisory
Alpine:v3.20thunderbird91.3.2-r0ALPINE-CVE-2021-29951
Alpine:v3.21thunderbird91.3.2-r0ALPINE-CVE-2021-29951
Alpine:v3.22thunderbird91.3.2-r0ALPINE-CVE-2021-29951
Alpine:v3.23thunderbird91.3.2-r0ALPINE-CVE-2021-29951

Affected products (as reported)

VendorProductVersions
Mozilla Thunderbird unspecified – before 78.10.1
Mozilla Firefox unspecified – before 87
Mozilla Firefox ESR unspecified – before 78.10.1

References