vulnerability
MFSA2025-54 Thunderbird: Security Vulnerabilities fixed in Thunderbird 140 (CVE-2025-6435)
| Severity | CVSS | Published | Added | Modified |
|---|---|---|---|---|
| 9 | (AV:N/AC:M/Au:N/C:C/I:C/A:C) | Jun 24, 2025 | Jul 3, 2025 | Apr 15, 2026 |
Severity
9
CVSS
(AV:N/AC:M/Au:N/C:C/I:C/A:C)
Published
Jun 24, 2025
Added
Jul 3, 2025
Modified
Apr 15, 2026
Description
If a user saved a response from the Network tab in Devtools using the Save As context menu option, that file may not have been saved with the `.download` file extension. This could have led to the user inadvertently running a malicious executable. This vulnerability was fixed in Firefox 140 and Thunderbird 140.
Solution
mozilla-thunderbird-upgrade-140_0
Rapid7 Labs
2026 Global Threat Landscape Report
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