CVE-2026-0877

Severity CVSS v4.0:

Pending analysis

Type:

CWE-693 Protection Mechanism Failure

Publication date:

13/01/2026

Last modified:

13/04/2026

Description

Mitigation bypass in the DOM: Security component. This vulnerability was fixed in Firefox 147, Firefox ESR 115.32, Firefox ESR 140.7, Thunderbird 147, and Thunderbird 140.7.

Impact

Vector 3.x

CVSS:3.1/AV:N/AC:L/PR:N/UI:R/S:U/C:H/I:H/A:N CVSS v3.1 Severity and Metrics:

Base Score: 8.10 HIGH
Vector: CVSS:3.1/AV:N/AC:L/PR:N/UI:R/S:U/C:H/I:H/A:N

Attack Vector (AV): Network
Attack Complexity (AC): Low
Privileges Required (PR): None
User Interaction (UI): Required
Scope (S): Unchanged
Confidentiality (C): High
Integrity (I): High
Availability (A): None

Base Score 3.x

8.10

Severity 3.x

HIGH

Vulnerable products and versions

CPE	From	Up to
cpe:2.3:a:mozilla:firefox:::::esr:::*		115.32.0 (excluding)
cpe:2.3:a:mozilla:firefox:::::-:::*		147.0 (excluding)
cpe:2.3:a:mozilla:firefox:::::esr:::*	128.0 (including)	140.7.0 (excluding)
cpe:2.3:a:mozilla:thunderbird:::::esr:::*		140.7.0 (excluding)
cpe:2.3:a:mozilla:thunderbird:::::-:::*		147.0 (excluding)

To consult the complete list of CPE names with products and versions, see this page

CVE-2026-0877

Description

Impact

Vulnerable products and versions

References to Advisories, Solutions, and Tools