CVE-2026-4696

Severity CVSS v4.0:

Pending analysis

Type:

CWE-416 Use After Free

Publication date:

24/03/2026

Last modified:

13/04/2026

Description

Use-after-free in the Layout: Text and Fonts component. This vulnerability was fixed in Firefox 149, Firefox ESR 115.34, Firefox ESR 140.9, Thunderbird 149, and Thunderbird 140.9.

Impact

Vector 3.x

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

Base Score: 9.80 CRITICAL
Vector: CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:H/I:H/A:H

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

Base Score 3.x

9.80

Severity 3.x

CRITICAL

Vulnerable products and versions

CPE	From	Up to
cpe:2.3:a:mozilla:firefox:::::esr:::*		115.34.0 (excluding)
cpe:2.3:a:mozilla:firefox:::::-:::*		149.0 (excluding)
cpe:2.3:a:mozilla:firefox:::::esr:::*	128.0 (including)	140.9.0 (excluding)

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

CVE-2026-4696

Description

Impact

Vulnerable products and versions

References to Advisories, Solutions, and Tools