CVE-2026-4634
Published:April 02, 2026
Updated:April 20, 2026
A flaw was found in Keycloak. An unauthenticated attacker can exploit this vulnerability by sending a specially crafted POST request with an excessively long scope parameter to the OpenID Connect (OIDC) token endpoint. This leads to high resource consumption and prolonged processing times, ultimately resulting in a Denial of Service (DoS) for the Keycloak server.
Affected Packages
https://github.com/keycloak/keycloak.git (GITHUB):
Affected version(s) >=1.0.0.Final <26.2.15Fix Suggestion:
Update to version 26.2.15https://github.com/keycloak/keycloak.git (GITHUB):
Affected version(s) >=26.5.0 <26.5.7Fix Suggestion:
Update to version 26.5.7https://github.com/keycloak/keycloak.git (GITHUB):
Affected version(s) >=26.4.0 <26.4.11Fix Suggestion:
Update to version 26.4.11org.keycloak:keycloak-services (JAVA):
Affected version(s) >=1.0-alpha-1 <26.5.7Fix Suggestion:
Update to version 26.5.7org.keycloak:keycloak-services (JAVA):
Affected version(s) >=26.5.0 <26.5.7Fix Suggestion:
Update to version 26.5.7Related Resources (10)
Do you need more information?
Contact UsCVSS v4
Base Score:
8.7
Attack Vector
NETWORK
Attack Complexity
LOW
Attack Requirements
NONE
Privileges Required
NONE
User Interaction
NONE
Vulnerable System Confidentiality
NONE
Vulnerable System Integrity
NONE
Vulnerable System Availability
HIGH
Subsequent System Confidentiality
NONE
Subsequent System Integrity
NONE
Subsequent System Availability
NONE
CVSS v3
Base Score:
7.5
Attack Vector
NETWORK
Attack Complexity
LOW
Privileges Required
NONE
User Interaction
NONE
Scope
UNCHANGED
Confidentiality
NONE
Integrity
NONE
Availability
HIGH
Weakness Type (CWE)
Excessive Platform Resource Consumption within a Loop
EPSS
Base Score:
0.07
