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MEDIUM

Keycloak: keycloak: attacker can re-enable and take over disabled clients via registration access token

Published Jun 25, 2026

Description

A flaw was found in Keycloak's client registration service. A remote attacker, possessing a previously issued Registration Access Token (RAT), could exploit this vulnerability to re-enable a client that an administrator had explicitly disabled. This bypasses security controls, allowing the attacker to reset the client's secret and potentially regain privileged API access. The primary impact includes unauthorized information disclosure and potential integrity compromise.

Affected products

Remediation

Vendor solution

To mitigate this issue, restrict network access to the Keycloak Dynamic Client Registration endpoint. Configure network firewalls to allow connections only from trusted hosts or networks that legitimately require access to this functionality. This limits the exposure of the vulnerable endpoint to unauthorized access attempts.

Red Hat statement

A Moderate flaw was found in Keycloak where a disabled client can be re-enabled by an attacker who retains a Registration Access Token (RAT) from a prior legitimate client registration. This allows the attacker to bypass the administrator's explicit intent to disable the client, reset its secret, and restore OAuth client_credentials capability, potentially leading to unauthorized access to resources.

Red Hat mitigation

To mitigate this issue, restrict network access to the Keycloak Dynamic Client Registration endpoint. Configure network firewalls to allow connections only from trusted hosts or networks that legitimately require access to this functionality. This limits the exposure of the vulnerable endpoint to unauthorized access attempts.

Metrics

Weaknesses (1)

References (8)

Change history (0)

No recorded changes yet.

Sources
CVE.org / MITRE
Status PUBLISHED
Assigner redhat
Published Jun 25, 2026
Updated Jun 29, 2026
Reserved May 27, 2026
CISA Vulnrichment
Updated Jun 29, 2026
NVD
Status Analyzed
Modified Jul 1, 2026
Red Hat
Severity Moderate
Public date Jun 25, 2026