Medium (6.5). EPSS 2.3% chance of exploitation in the next 30 days.
A vulnerability where a WebExtension can run content scripts in disallowed contexts following navigation or other events. This allows for potential privilege escalation by the WebExtension on sites where content scripts should not be run. This vulnerability affects Firefox ESR < 60.3 and Firefox < 63.
Severity
CVSS 3.0
6.5 medium
CVSS:3.0/AV:N/AC:L/PR:N/UI:R/S:U/C:N/I:H/A:N
EPSS
2.3% chance of exploitation in the next 30 days; higher than 83% of CVEs (scores of 2026-10-31)