CVE-2024-9391: Mozilla Firefox

Medium severity, CVSS 6.5. EPSS: 0.3% chance of exploitation in the next 30 days.

A user who enables full-screen mode on a specially crafted web page could potentially be prevented from exiting full screen mode. This may allow spoofing of other sites as the address bar is no longer visible. *This bug only affects Firefox Focus for Android. Other versions of Firefox are unaffected.* This vulnerability affects Firefox < 131.

Affected products

• Mozilla Firefox: before 131.0 (fixed in 131.0)

Published 2024-10-01. Last modified 2026-06-17.