CVE-2026-16387EPSS p9.4%

CVE-2026-16387CVE-2026-16387

mozilla / firefox

Description

Site isolation issue in the Networking component. This vulnerability was fixed in Firefox 153, Firefox ESR 140.13, Thunderbird 153, and Thunderbird 140.13.

Scoring

CVSS 9.8 ()
VectorCVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:H/I:H/A:H
EPSS0.20% probability of exploitation · percentile 9.4% · 2026-10-05T12:00:23Z
Last modified2026-07-24
Sourced from NVD + FIRST.org EPSS. Curated for EU compliance use cases by Adam Lundqvist, Founder at SQUR.