CVE-2026-89298 Red Hat CVE debrief

Who should care

Defenders managing Keycloak instances, especially those with read-only administrators accessing client registration endpoints, should assess exposure and potential impact on their environments.

Why it matters

CVE-2026-89298 is a medium-severity flaw in Keycloak's Dynamic Client Registration service that could allow read-only administrators to obtain confidential client secrets and potentially escalate privileges. Defenders managing Keycloak instances should verify exposure, restrict access to client registration endpoints, and monitor for potential privilege escalation.

• Potential unauthorized access to client accounts by read-only administrators
• Possible privilege escalation within the realm
• Need for verification of Keycloak instance exposure to Dynamic Client Registration service
• Requirement to restrict access to client registration endpoints

Technical summary

The flaw occurs when a user with the view-clients role accesses the client registration endpoint to retrieve client details. Due to a failure to mask sensitive information, the service returns the client's confidential secret in cleartext. This allows potential attackers to obtain sensitive information that could be used to gain unauthorized access to client accounts. The issue highlights the importance of proper access controls and data masking in client registration services. Keycloak instances with exposed Dynamic Client Registration services are particularly vulnerable to this issue.

Defensive priority

Defenders should prioritize verifying exposure of Keycloak instances to the Dynamic Client Registration service, especially in environments where read-only administrators have access to client registration endpoints. They should also assess the impact of potential privilege escalation within the realm.

Recommended defensive actions

• Verify Keycloak instances are not exposing the Dynamic Client Registration service to unauthorized users
• Restrict access to client registration endpoints for read-only administrators
• Monitor for potential privilege escalation within the realm
• Review and update access controls for client details in Keycloak
• Perform a thorough review of Keycloak instance configurations to ensure secure client registration endpoint access
• Implement additional monitoring to detect unauthorized access attempts on client accounts
• Conduct regular security audits to identify potential vulnerabilities in Keycloak deployments

Evidence notes

The CVE record and NVD entry provide details about the flaw in Keycloak's Dynamic Client Registration service. However, the corpus does not establish specific versions affected or fixed, exploitation in the wild, or detailed impact beyond potential privilege escalation.

Sources and references

Methodology and review provenance

AI-assisted synthesis based on stored public vulnerability evidence. System validation, approval state, and publication status do not by themselves establish human review of this revision. PatchSiren helps prioritize defensive review and does not prove exposure or remediation on any system.