CVE-2025-6434EPSS p18.9%

CVE-2025-6434CVE-2025-6434

mozilla / firefox

Description

The exception page for the HTTPS-Only feature, displayed when a website is opened via HTTP, lacked an anti-clickjacking delay, potentially allowing an attacker to trick a user into granting an exception and loading a webpage over HTTP. This vulnerability was fixed in Firefox 140 and Thunderbird 140.

Scoring

CVSS 4.3 ()
VectorCVSS:3.1/AV:N/AC:L/PR:N/UI:R/S:U/C:N/I:L/A:N
EPSS0.28% probability of exploitation · percentile 18.9% · 2026-10-05T12:00:23Z
Last modified2026-09-30
Sourced from NVD + FIRST.org EPSS. Curated for EU compliance use cases by Adam Lundqvist, Founder at SQUR.