CVE-2026-16387: firefox before 140.13.0 (exclusive), before 153.0.0 (exclusive); +1 more affected products

CVE-2026-16387. CVSS 3.1 base score 9.8 (CRITICAL, Source advisory). EPSS 0.00204 (percentile 0.09879), scored 24-Oct-2026.

Affected technology

firefox · before 140.13.0 (exclusive)
mozilla

firefox · before 153.0.0 (exclusive)
mozilla

thunderbird · before 140.13.0 (exclusive)
mozilla

thunderbird · from 141.0 (inclusive), before 153.0 (exclusive)
mozilla

Component: Not specified by the source

Attack conditions (Source advisory, CVSS 3.1): Network (remote) · No privileges required · No user interaction required

What an attacker can do

Source advisory’s CVSS 3.1 assessment (base score 9.8/10) rates confidentiality, integrity and availability impact as high. The description does not specify what an attacker can achieve beyond these rated impacts.

Published 25-Oct-2026 01:29 UTC

CWE: CWE-200, CWE-284, CWE-346
CCR priority: 39.3 /100 (P4)
CVSS 3.1: 9.8 /10 · CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:H/I:H/A:H · Source advisory
EPSS: 0.00204 · percentile 0.09879 · 2026-10-24
KEV: no

Provenance

NVD CVE API 2.0 · Source record · observed 2026-10-25 01:28:19.133527+00:00 UTC

Stable permalink: https://cybercodered.org/item/cve-cve-2026-16387.html