URL Truncation Vulnerability in Firefox and Thunderbird by Mozilla
CVE-2025-8043

Currently unrated

Key Information:

Vendor: Mozilla
Status: Firefox; Thunderbird
Vendor: CVE Published:; 22 July 2025

What is CVE-2025-8043?

This vulnerability arises from the incorrect truncation of URLs in Firefox and Thunderbird, where URLs are truncated at the beginning instead of around the origin. This flaw potentially exposes users to unexpected behavior and security risks, emphasizing the importance of updating to the latest versions.

Affected Version(s)

Firefox < 141

Thunderbird < 141

References

https://bugzilla.mozilla.org/show_bug.cgi?id=1970209

https://www.mozilla.org/security/advisories/mfsa2025-56/

https://www.mozilla.org/security/advisories/mfsa2025-61/

Download the Critical Vulnerability Management Cheat Sheet

Timeline

Vulnerability published
Jul 22, 2025
Vulnerability Reserved
Jul 22, 2025

Credit

alayersattackers