CVE-2025-6435

Published: Jun 24, 2025Modified: Apr 13, 2026

8.1

Vector

CVSS:3.1/AV:N/AC:H/PR:N/UI:N/S:U/C:H/I:H/A:H

Exploitability: 2.2 / Impact: 5.9

Source: 134c704f-9b21-4f2e-91b3-4a467353bcc0 (Secondary)

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.

Affected (2)

Products: Mozilla: Firefox, Thunderbird

2 products

Configuration A

2 vulnerable

Vulnerable Software	Affected Versions
Mozilla Firefox	Before 140.0
Mozilla Thunderbird	Before 140.0

Related CWEs

Unrestricted Upload of File with Dangerous Type

The product allows the upload or transfer of dangerous file types that are automatically processed within its environment.

References (4)

https://bugzilla.mozilla.org/show_bug.cgi?id=1950056

Source: security@mozilla.org

Permissions Required

https://bugzilla.mozilla.org/show_bug.cgi?id=1961777

Source: security@mozilla.org

Permissions Required

https://www.mozilla.org/security/advisories/mfsa2025-51/

Source: security@mozilla.org

Vendor Advisory

https://www.mozilla.org/security/advisories/mfsa2025-54/

Source: security@mozilla.org

Vendor Advisory

Timeline

No history available yet.