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CVE-2026-4718

HIGH CVSS 3.1: 8.1 EPSS 0.01%
Updated Mar 25, 2026
Firefox
Parameter Value
CVSS 8.1 (HIGH)
Affected Versions before 149.0
Fixed In 140.9.0
Type CWE-758
Vendor Firefox
Public PoC No

Undefined behavior in the WebRTC: Signaling 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
Required
User action required

Impact Assessment

Confidentiality
High
Complete data leak
Integrity
High
Complete data modification
Availability
None
No disruption

CVSS Vector v3.1

Weakness Type (CWE)

Vulnerable Products 4

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
Mozilla Thunderbird
cpe:2.3:a:mozilla:thunderbird:*:*:*:*:esr:*:*:*
140.9.0
Mozilla Thunderbird
cpe:2.3:a:mozilla:thunderbird:*:*:*:*:-:*:*:*
149.0