CVE-2025-5266EPSS p23.5%

CVE-2025-5266CVE-2025-5266

mozilla / firefox

Description

Script elements loading cross-origin resources generated load and error events which leaked information enabling XS-Leaks attacks. This vulnerability was fixed in Firefox 139, Firefox ESR 128.11, Thunderbird 139, and Thunderbird 128.11.

Scoring

CVSS 4.3 ()
VectorCVSS:3.1/AV:N/AC:L/PR:N/UI:R/S:U/C:L/I:N/A:N
EPSS0.33% probability of exploitation · percentile 23.5% · 2026-10-05T12:00:23Z
Last modified2026-10-05
Sourced from NVD + FIRST.org EPSS. Curated for EU compliance use cases by Adam Lundqvist, Founder at SQUR.