CVE-2026-9705 in Keycloak
Summary
by MITRE • 06/25/2026
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.
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Analysis
by VulDB Data Team • 06/25/2026
This vulnerability resides within Keycloak's client registration service architecture, specifically targeting the token-based authorization mechanisms that govern client lifecycle management operations. The flaw represents a critical authorization bypass issue where an attacker with a valid Registration Access Token can manipulate client state regardless of administrative restrictions. The vulnerability stems from insufficient validation of administrative actions within the client registration endpoint, allowing privilege escalation through token manipulation. This type of weakness aligns with CWE-285, which addresses improper authorization in authentication systems, and specifically manifests as an authorization bypass vulnerability that undermines the principle of least privilege.
The technical exploitation occurs when a remote attacker leverages a previously issued Registration Access Token to perform administrative operations on disabled clients. The system fails to properly validate whether the token holder has elevated privileges for state modification operations, particularly those involving re-enabling previously disabled entities. This flaw enables attackers to reset client secrets and subsequently regain access to privileged API endpoints that were intentionally restricted by administrators. The vulnerability exploits the trust model inherent in token-based authentication systems where valid tokens are assumed to carry appropriate authorization levels without sufficient context validation.
The operational impact of this vulnerability extends beyond simple unauthorized access, creating potential data exposure scenarios where attackers can re-enable malicious clients and maintain persistent access to sensitive resources. The ability to reset client secrets allows for prolonged unauthorized operations within the system, as the attacker can regenerate valid credentials for previously disabled entities. This compromise affects both confidentiality and integrity aspects of the security model, enabling information disclosure through API access and potential data manipulation through privileged client operations. The vulnerability essentially undermines the administrative controls that should prevent unauthorized reactivation of security-relevant components.
Mitigation strategies should focus on implementing stricter authorization validation within the client registration service, ensuring that administrative operations require explicit privilege verification regardless of token validity. Organizations must enforce additional authentication layers for critical operations such as enabling/disabling clients and resetting secrets. The implementation should include enhanced session management controls and time-based token expiration mechanisms to limit the window of opportunity for exploitation. Security configurations should be reviewed to ensure proper separation of duties between regular client registration operations and administrative privilege operations, aligning with defense-in-depth principles outlined in cybersecurity frameworks such as NIST SP 800-53 and ISO/IEC 27001 standards.