Description
It was possible to craft an email that showed a tracking link as an attachment. If the user attempted to open the attachment, Thunderbird automatically accessed the link. The configuration to block remote content did not prevent that. Thunderbird has been fixed to no longer allow access to web pages listed in the X-Mozilla-External-Attachment-URL header of an email. This vulnerability was fixed in Thunderbird 128.10.1 and Thunderbird 138.0.1.
Product status
138.0.1 (rpm)
Credits
Dario Weißer
References
lists.debian.org/debian-lts-announce/2025/05/msg00022.html
bugzilla.mozilla.org/show_bug.cgi?id=1960412
www.mozilla.org/security/advisories/mfsa2025-34/
www.mozilla.org/security/advisories/mfsa2025-35/