CVE-2026-107889

MEDIUM CVSS 3.1: 5.5 EPSS 0.27%
Updated Oct 13, 2026
Keycloak
Parameter Value
CVSS 5.5 (MEDIUM)
Type CWE-79 (Cross-Site Scripting (XSS))
Vendor Keycloak
Public PoC No

A flaw was found in the login theme rendering component of Keycloak. The issue occurs because the security filter responsible for cleaning user input can be bypassed, allowing a realm administrator to store malicious scripts in display fields. This could result in unauthorized JavaScript execution in the browsers of users visiting the login page, potentially leading to data exposure or session interference.

Attack Parameters

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

Impact Assessment

Confidentiality
Low
Partial data leak
Integrity
Low
Partial data modification
Availability
None
No disruption

CVSS Vector v3.1