Name: CVE-2026-74979: Improper Access Control
Creator: Rapid7
Published: 2026-08-18T00:00:00.000Z
License: https://www.rapid7.com/legal/website-terms-of-use/
Keywords: CVE, CVE-2026-74979, CWE-284, CVSS 9.8, EPSS 0.00525

Mitigation bypass in the Add-ons Manager component. This vulnerability was fixed in Firefox 154, Firefox ESR 153.1, Thunderbird 154, and Thunderbird 153.1.

CVSS Details

CVSS 3.1 Base Score: 9.8
CVSS 3.1 Vector: (CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:H/I:H/A:H)

Covered by Rapid7

Product	Vendor Advisory	Solution File	Added	Published
Mfsa2026 74	—	Upgrade to Mozilla Firefox version 154.0Upgrade to the latest version of Mozilla Firefox	Aug 18, 2026	Aug 18, 2026
Mfsa2026 77	—	Upgrade to the latest version of Mozilla FirefoxUpgrade to Mozilla Firefox ESR version 153.1	Aug 18, 2026	Aug 18, 2026
Mozilla Thunderbird	—	Upgrade to the latest version of Mozilla ThunderbirdUpgrade to Mozilla Thunderbird version 153.1	Aug 18, 2026	Aug 18, 2026

Prioritise with Active Threat Intelligence

With curated Threat Intelligence, you can see which vulnerabilities truly put you at risk, prioritize what matters most, and act before attackers do.

Explore Intelligence Hub

MDR Buyer's Guide

Global Threat Landscape Report

Grow your business

CVSS Details

Covered by Rapid7

Prioritise with Active Threat Intelligence