CVE-2025-4083

CVE-2025-4083: Process isolation bypass using "javascript:" URI links in cross-origin frames

Published April 29, 2025
Last update April 13, 2026

CVSS base score

What the vulnerability does

Description

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 was fixed in Firefox 138, Firefox ESR 128.10, Firefox ESR 115.23, Thunderbird 138, and Thunderbird 128.10.

Key dates

Disclosure timeline

April 29, 2025 CVE published
April 13, 2026 Record updated