CVE-2025-6435CWE-434unrestricted-file-upload

CVE-2025-6435

High · published June 24, 2025

CVSS v3.1
8.1
EPSS
0%
Percentile
38.7
In the wild
Unconfirmed
What it is

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.

The record
Technical detail
CVSS v3.1
8.1 · HIGH
Vector
CVSS:3.1/AV:N/AC:H/PR:N/UI:N/S:U/C:H/I:H/A:H
CVSS v4.0
Not supplied
EPSS
0.00457 · 38.7th percentile
Weakness
CWE-434 · Unrestricted Upload of File with Dangerous Type
Published
2025-06-24T17:15Z
Affected products (2)
ProductVersionsFixed in
mozilla/firefox< 140.0140.0
mozilla/thunderbird< 140.0140.0
References (4)
https://bugzilla.mozilla.org/show_bug.cgi?id=1950056 · [email protected]https://bugzilla.mozilla.org/show_bug.cgi?id=1961777 · [email protected]https://www.mozilla.org/security/advisories/mfsa2025-51/ · [email protected]https://www.mozilla.org/security/advisories/mfsa2025-54/ · [email protected]
EPSS history
Timeline
  • 24 JUN 12:28Z
    Save as in Devtools could download files without sanitizing the extension
    cvelistv5