CVE-2025-6433 Affecting firefox package, versions <140.0-1


Severity

Recommended
low

Based on default assessment until relevant scores are available.

Threat Intelligence

EPSS
0.03% (8th percentile)

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  • Snyk IDSNYK-DEBIANUNSTABLE-FIREFOX-10498723
  • published25 Jun 2025
  • disclosed24 Jun 2025

Introduced: 24 Jun 2025

NewCVE-2025-6433  (opens in a new tab)

How to fix?

Upgrade Debian:unstable firefox to version 140.0-1 or higher.

NVD Description

Note: Versions mentioned in the description apply only to the upstream firefox package and not the firefox package as distributed by Debian. See How to fix? for Debian:unstable relevant fixed versions and status.

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 affects Firefox < 140.

CVSS Base Scores

version 3.1