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CVE-2026-4716

CRITICAL CVSS 3.1: 9.1 EPSS 0.02%
Updated Mar 25, 2026
Firefox
Parameter Value
CVSS 9.1 (CRITICAL)
Affected Versions before 149.0
Fixed In 140.9.0
Type CWE-908 (Use of Uninitialized Resource)
Vendor Firefox
Public PoC No

Incorrect boundary conditions, uninitialized memory in the JavaScript Engine component. This vulnerability affects Firefox < 149, Firefox ESR < 140.9, Thunderbird < 149, and Thunderbird < 140.9.

Attack Parameters

Attack Vector
Network
Can be exploited remotely
Attack Complexity
Low
Easy to exploit
Privileges Required
None
No privileges needed
User Interaction
None
No user interaction needed

Impact Assessment

Confidentiality
High
Complete data leak
Integrity
None
No data modification
Availability
High
Complete denial of service

CVSS Vector v3.1

Vulnerable Products 2

Configuration From (including) Up to (excluding)
Mozilla Firefox
cpe:2.3:a:mozilla:firefox:*:*:*:*:esr:*:*:*
140.9.0
Mozilla Firefox
cpe:2.3:a:mozilla:firefox:*:*:*:*:-:*:*:*
149.0