Red Hat: CVE-2025-3909: thunderbird: JavaScript Execution via Spoofed PDF Attachment and file:/// Link (Multiple Advisories)
Description
Thunderbird's handling of the X-Mozilla-External-Attachment-URL header can be exploited to execute JavaScript in the file:/// context. By crafting a nested email attachment (message/rfc822) and setting its content type to application/pdf, Thunderbird may incorrectly render it as HTML when opened, allowing the embedded JavaScript to run without requiring a file download. This behavior relies on Thunderbird auto-saving the attachment to /tmp and linking to it via the file:/// protocol, potentially enabling JavaScript execution as part of the HTML. This vulnerability affects Thunderbird < 128.10.1 and Thunderbird < 138.0.1.
Solution(s)
- redhat-upgrade-thunderbird
- redhat-upgrade-thunderbird-debuginfo
- redhat-upgrade-thunderbird-debugsource
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