CVE-2025-6429EPSS p27.0%

CVE-2025-6429CVE-2025-6429

mozilla / firefox

Description

Firefox could have incorrectly parsed a URL and rewritten it to the youtube.com domain when parsing the URL specified in an `embed` tag. This could have bypassed website security checks that restricted which domains users were allowed to embed. This vulnerability was fixed in Firefox 140, Firefox ESR 128.12, Thunderbird 140, and Thunderbird 128.12.

Scoring

CVSS 6.5 ()
VectorCVSS:3.1/AV:N/AC:L/PR:N/UI:R/S:U/C:N/I:H/A:N
EPSS0.36% probability of exploitation · percentile 27.0% · 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.