CVE-2025-6433

critical · 9.8

If a user visited a webpage with an invalid TLS certificate, and granted an exception, the webpage was able to provide a WebAuthn challenge that the user would be prompted to complete. This is in violation of the WebAuthN spec which requires "a secure transport established without errors". This vulnerability was fixed in Firefox 140 and Thunderbird 140.

9.8

CVSS

0.3%

EPSS (exploit prob.)

20th

EPSS percentile

2025-06-24

Published

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

Weaknesses

CWE-295

Affected products

Vendor	Product	Affected versions
mozilla	firefox	< 140.0

Check a specific version with /api/v1/cve/match.

References

https://bugzilla.mozilla.org/show_bug.cgi?id=1954033
https://www.mozilla.org/security/advisories/mfsa2025-51/
https://www.mozilla.org/security/advisories/mfsa2025-54/

Query this programmatically:

curl https://evil-db.io/api/v1/cve/CVE-2025-6433