High severity8.1NVD Advisory· Published Jun 24, 2025· Updated Apr 13, 2026

CVE-2025-6435

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 products

Mozilla Corporation/Firefox
cpe:2.3:a:mozilla:firefox:*:*:*:*:*:*:*:*
Range: <140.0
Mozilla Corporation/Thunderbird
cpe:2.3:a:mozilla:thunderbird:*:*:*:*:*:*:*:*
Range: <140.0

Patches

No patches discovered yet.

Vulnerability mechanics

AI mechanics synthesis has not run for this CVE yet.

References

www.mozilla.org/security/advisories/mfsa2025-51/nvdVendor Advisory
www.mozilla.org/security/advisories/mfsa2025-54/nvdVendor Advisory
bugzilla.mozilla.org/show_bug.cginvdPermissions Required
bugzilla.mozilla.org/show_bug.cginvdPermissions Required

News mentions

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cvss	0.526
epss	0.000
exploit	0.000
kev	0.000
patch	0.000
ransomware	0.000