CVE-2026-6774 — Protection Mechanism Failure in Mozilla Firefox

CWE-693 — Protection Mechanism FailureCWE-358 — Improperly Implemented Security Check for Standard6 documents5 sources
Severity
5.4MEDIUMNVD
EPSS
0.0%
top 88.88%
CISA KEV
Not in KEV
Exploit
No known exploits
Affected products
2
Mozilla FirefoxMozilla Thunderbird
Timeline
PublishedApr 21

Description

Mitigation bypass in the DOM: Security component. This vulnerability was fixed in Firefox 150 and Thunderbird 150.

CVSS vector

CVSS:3.1/AV:N/AC:L/PR:L/UI:R/S:C/C:L/I:L/A:NExploitability: 2.3 | Impact: 2.7

Affected Packages2 packages

▶Mozillamozilla/firefox< Firefox 150
▶Mozillamozilla/thunderbird< Thunderbird 150

🔴Vulnerability Details

1
GHSA
GHSA-gp6f-8rr3-wxrg: Mitigation bypass in the DOM: Security component↗2026-04-21
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📋Vendor Advisories

3
Red Hat
Firefox: Firefox: Mitigation bypass in DOM Security component↗2026-04-21
▶
Mozilla
Mozilla Foundation Security Advisory 2026-33: CVE-2026-6774↗
▶
Mozilla
Mozilla Foundation Security Advisory 2026-30: CVE-2026-6774↗
▶

💬Community

1
Bugzilla
CVE-2026-6774 Firefox: Firefox: Mitigation bypass in DOM Security component↗2026-04-21
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CVE-2026-6774 — Protection Mechanism Failure in Mozilla | cvebase