Vulnerabilities
Vulnerable Software

Vulnerability Details CVE-2025-3909

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.
Exploit prediction scoring system (EPSS) score
EPSS Score 0.001
EPSS Ranking 16.3%
CVSS Severity
CVSS v3 Score 6.5
Products affected by CVE-2025-3909


Contact Us

Shodan ® - All rights reserved