CVE-2026-4629 in Keycloak
Summary
by MITRE • 06/30/2026
A flaw was found in Keycloak. A highly privileged user with `manage-clients` permission can exploit this vulnerability by injecting a hardcoded role mapper into any client. This action allows the user to bypass existing scope restrictions and inject the `realm-admin` role into generated tokens, resulting in privilege escalation and full administrative access to the realm.
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Analysis
by VulDB Data Team • 06/30/2026
This vulnerability represents a critical privilege escalation flaw within the Keycloak identity and access management platform that directly undermines the core security model of role-based access control. The issue stems from insufficient validation mechanisms when processing role mappers within client configurations, allowing attackers with relatively limited permissions to manipulate the authentication flow. The vulnerability is particularly concerning because it enables a user with only `manage-clients` permission to bypass established security boundaries and escalate privileges to full administrative access over the entire realm. This represents a fundamental breakdown in the principle of least privilege that Keycloak is designed to enforce.
The technical exploitation occurs through the injection of a hardcoded role mapper into client configurations, which then propagates through the token generation process without proper validation checks. When this malicious role mapper is processed during authentication, it injects the `realm-admin` role into generated access tokens regardless of the original scope restrictions imposed on the user. The vulnerability leverages the trust model within Keycloak's token processing pipeline where role mappings are not adequately verified against the permissions of the requesting user. This flaw operates at the intersection of multiple security controls and demonstrates how a single validation gap can completely compromise the entire authorization framework.
The operational impact of this vulnerability is severe as it allows attackers to gain complete administrative control over all resources within the affected realm without requiring additional credentials or elevated privileges. Once exploited, the attacker can modify user permissions, create new users, access sensitive data, and potentially exfiltrate information from the entire Keycloak deployment. The attack vector requires minimal privileges initially, making it particularly dangerous as it can be exploited by insiders with legitimate administrative access to client configurations or by external attackers who have obtained such credentials through other means. This vulnerability essentially provides a backdoor path that bypasses all existing security controls and scope restrictions.
Mitigation strategies should focus on implementing strict validation of role mappers during client configuration modifications and enforcing additional authorization checks when processing role mappings. Organizations should immediately restrict the `manage-clients` permission to only trusted administrators and implement monitoring for unusual client configuration changes. The recommended approach includes enabling detailed audit logging of all client management activities, implementing role mapper validation rules that prevent injection of administrative roles, and ensuring proper segregation of duties within Keycloak deployments. This vulnerability aligns with CWE-284 (Improper Access Control) and CWE-352 (Cross-Site Request Forgery) categories, and represents a significant concern under the ATT&CK framework's privilege escalation techniques where attackers exploit application-level flaws to gain elevated access rights. Organizations should also consider implementing multi-factor authentication and regular security assessments of their Keycloak configurations to prevent similar vulnerabilities from being exploited in production environments.