CVE-2025-55031: Mozilla Firefox

Critical severity, CVSS 9.8. EPSS: 0.4% chance of exploitation in the next 30 days.

Malicious pages could use Firefox for iOS to pass FIDO: links to the OS and trigger the hybrid passkey transport. An attacker within Bluetooth range could have used this to trick the user into using their passkey to log the attacker's computer into the target account. This vulnerability was fixed in Firefox for iOS 142 and Focus for iOS 142.

Affected products

• Mozilla Firefox: before 142.0 (fixed in 142.0)
• Mozilla Firefox Focus: before 142.0 (fixed in 142.0)

Published 2025-08-19. Last modified 2026-09-30.