CVE-2026-109773
Firefox: Denial-of-service in the Sync component
Mozilla FirefoxApplications & CMS
CVSS
6.5MediumExploitationNo known exploitationNot in CISA KEV, which does not prove it is unexploitedCISA KEV
Exploit odds (EPSS)0.24%Chance of exploitation activity in the next 30 days, higher than 14% of CVEs. Scored 23 Oct 2026FIRST EPSS
Fixed inNone listedNo source names a fixed version. Check the vendor advisory below
What fixes it
No source in this snapshot names a fixed version. The vendor advisories under References are the place to check.
Description
Denial-of-service in the Sync component. This vulnerability was fixed in Firefox 158 and Thunderbird 158.
Text from CVE List
Affected versions 2
- Firefoxunaffected: 158CVE List
- Thunderbirdunaffected: 158CVE List