vulnerability
MFSA2025-35 Thunderbird: Security Vulnerabilities fixed in Thunderbird 138.0.1 (CVE-2025-3909)
| Severity | CVSS | Published | Added | Modified |
|---|---|---|---|---|
| 8 | (AV:N/AC:M/Au:N/C:P/I:C/A:N) | May 13, 2025 | May 15, 2025 | Jun 13, 2025 |
Severity
8
CVSS
(AV:N/AC:M/Au:N/C:P/I:C/A:N)
Published
May 13, 2025
Added
May 15, 2025
Modified
Jun 13, 2025
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
Solution
mozilla-thunderbird-upgrade-138_0_1
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