High (8.8) in mozilla. EPSS 0.7% chance of exploitation in the next 30 days.
Permission prompts for opening external schemes were only shown for <code>ContentPrincipals</code> resulting in extensions being able to open them without user interaction via <code>ExpandedPrincipals</code>. This could lead to further malicious actions such as downloading files or interacting with software already installed on the system. This vulnerability affects Firefox < 110, Thunderbird < 102.8, and Firefox ESR < 102.8.
Severity
CVSS 3.1
8.8 high
CVSS:3.1/AV:N/AC:L/PR:N/UI:R/S:U/C:H/I:H/A:H
EPSS
0.7% chance of exploitation in the next 30 days; higher than 52% of CVEs (scores of 2026-10-31)