CVE-2026-2366 is a security vulnerability identified in the Red Hat Build of Keycloak, an open-source identity and access management solution widely used for authentication and authorization services. The vulnerability exists in the Admin API related to the Organizations feature. Specifically, it allows any authenticated user, regardless of their privilege level, to enumerate the organization memberships of other users if the attacker knows the victim's unique identifier (UUID). This is an authorization bypass flaw because the API fails to properly restrict access to organization membership data, which should normally be accessible only to administrators or authorized personnel. The vulnerability does not require administrative privileges or user interaction but does require the attacker to be authenticated. The attack complexity is considered high because the attacker must know the UUID of the target user, which is not trivial to obtain. The vulnerability results in limited confidentiality impact by disclosing organization membership information, but it does not affect data integrity or system availability. The CVSS v3.1 base score is 3.1, reflecting low severity due to limited impact and high attack complexity. No patches or exploits are currently reported, but the issue is publicly disclosed and should be addressed by applying updates once available or implementing compensating controls. This flaw highlights the importance of strict access control enforcement in identity management APIs, especially for sensitive organizational data.

The primary impact of CVE-2026-2366 is limited information disclosure, specifically unauthorized enumeration of organization memberships of users within Keycloak. While this does not directly compromise system integrity or availability, it can aid attackers in reconnaissance efforts by revealing organizational structure and relationships. Such information could be leveraged in targeted phishing, social engineering, or subsequent privilege escalation attempts. Organizations relying on Keycloak for identity management may face privacy concerns and potential compliance issues if sensitive organizational membership data is exposed. The requirement for authentication and knowledge of UUIDs limits the scope of exploitation, reducing the overall risk. However, in environments with many users and complex organizational hierarchies, the vulnerability could facilitate lateral movement or insider threat activities. The absence of known exploits in the wild suggests limited active exploitation, but the public disclosure increases the risk of future attacks. Enterprises, cloud service providers, and government agencies using Red Hat's Keycloak build should consider the potential impact on confidentiality and take appropriate measures to mitigate exposure.

To mitigate CVE-2026-2366, organizations should first verify whether the Organizations feature in Keycloak is enabled and assess if it is necessary for their deployment. If not required, disabling this feature can eliminate the attack surface. For environments where the feature is essential, administrators should implement strict access control policies to restrict API access to trusted administrative users only, using network segmentation, API gateways, or identity-based access controls. Monitoring and logging API calls related to organization membership enumeration can help detect suspicious activity. Additionally, organizations should apply any patches or updates released by Red Hat promptly once available. If patches are not yet released, consider implementing compensating controls such as rate limiting, anomaly detection, or additional authentication layers for sensitive API endpoints. Educating users about the importance of safeguarding UUIDs and minimizing their exposure can further reduce risk. Finally, conducting regular security assessments and penetration testing focused on identity management components can help identify and remediate similar authorization issues proactively.