CVE-2026-74956

Name of the Vulnerable Software and Affected Versions Firefox versions prior to 154 Firefox ESR versions prior to 153.1 Thunderbird versions prior to 154 Thunderbird versions prior to 153.1

Description A same-origin policy bypass exists within the DOM: Service Workers component. The same-origin policy is a critical security mechanism that restricts how a document or script loaded from one origin can interact with a resource from another origin.

Recommendations Update Firefox to version 154. Update Firefox ESR to version 153.1. Update Thunderbird to version 154. Update Thunderbird to version 153.1.