firefox: thunderbird: Process isolation bypass using "javascript:" URI links in cross-origin frames

A flaw was found in Firefox. The Mozilla Foundation's Security Advisory describes the following issue: A process isolation vulnerability in Firefox stemmed from improper handling of javascript: URIs, which could allow content to execute in the top-level document's process instead of the intended...

CVE-2025-4083

A process isolation vulnerability in Thunderbird stemmed from improper handling of javascript: URIs, which could allow content to execute in the top-level document's process instead of the intended frame, potentially enabling a sandbox escape. This vulnerability affects Firefox 138, Firefox ESR...