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CVE-2026-5735

CRITICAL CVSS 3.1: 9.8 EPSS 0.04%
Updated Apr 07, 2026
Mozilla
Parameter Value
CVSS 9.8 (CRITICAL)
Affected Versions before 149.0.2
Fixed In 149.0.2
Type CWE-787 (Out-of-bounds Write)
Vendor Mozilla
Public PoC No

Memory safety bugs present in Firefox 149.0.1 and Thunderbird 149.0.1. Some of these bugs showed evidence of memory corruption and we presume that with enough effort some of these could have been exploited to run arbitrary code. This vulnerability affects Firefox < 149.0.2 and Thunderbird < 149.0.2.

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
High
Complete data modification
Availability
High
Complete denial of service

CVSS Vector v3.1

Weakness Type (CWE)

Vulnerable Products 2

Configuration From (including) Up to (excluding)
Mozilla Firefox
cpe:2.3:a:mozilla:firefox:*:*:*:*:-:*:*:*
149.0.2
Mozilla Thunderbird
cpe:2.3:a:mozilla:thunderbird:*:*:*:*:-:*:*:*
149.0.2