VulnerabilityModified
CVE-2025-6433
This vulnerability was fixed in Firefox 140 and Thunderbird 140.
CRITICAL 9.8EPSS 0.26%
Does this matter?
High impact if exploited, but EPSS currently rates exploitation as unlikely (0.26%). Schedule it in the normal patch cycle and watch for a rise in EPSS or a public exploit.
Description
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.
- CVSS 3.1
- 9.8 CRITICALCVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:H/I:H/A:H
- EPSS
- 0.26% probability · 18th percentile
- CISA KEV
- Not listed
- Weakness
- CWE-295
- Affected
- mozilla/firefox
- Source
- security@mozilla.org
References
Source: NVD record, EPSS from FIRST.org, KEV from CISA. Refreshed daily.