CVE-2026-109778

HIGH CVSS 3.1: 8.8
Updated Oct 13, 2026
Firefox
Parameter Value
CVSS 8.8 (HIGH)
Type CWE-269 (Improper Privilege Management)
Vendor Firefox
Public PoC No

Privilege escalation in the WebExtensions component. This vulnerability was fixed in Firefox 158 and Firefox ESR 153.5.

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
High
Complete denial of service

CVSS Vector v3.1