CVE-2019-9806: Mozilla Firefox

High severity, CVSS 7.5. EPSS: 1.1% chance of exploitation in the next 30 days.

A vulnerability exists during authorization prompting for FTP transaction where successive modal prompts are displayed and cannot be immediately dismissed. This allows for a denial of service (DOS) attack. This vulnerability affects Firefox < 66.

Affected products

• Mozilla Firefox: before 66.0 (fixed in 66.0)

Published 2019-04-26. Last modified 2026-06-17.