CVE-2026-8948: Mozilla Firefox

Critical severity, CVSS 9.1. EPSS: 0.5% chance of exploitation in the next 30 days.

Same-origin policy bypass in the DOM: Networking component. This vulnerability was fixed in Firefox 151 and Thunderbird 151.

Affected products

• Mozilla Firefox: before 151.0.0 (fixed in 151.0.0)
• Mozilla Thunderbird: before 151.0.0 (fixed in 151.0.0)

Published 2026-05-19. Last modified 2026-07-15.