CVE-2026-0889: Mozilla Firefox

High severity, CVSS 7.5. EPSS: 0.6% chance of exploitation in the next 30 days.

Denial-of-service in the DOM: Service Workers component. This vulnerability was fixed in Firefox 147 and Thunderbird 147.

Affected products

• Mozilla Firefox: before 147.0 (fixed in 147.0)
• Mozilla Thunderbird: before 147.0 (fixed in 147.0)

Published 2026-01-13. Last modified 2026-06-17.