CVE-2026-3009 is an authorization bypass vulnerability identified in the Red Hat build of Keycloak version 26.4, specifically within the IdentityBrokerService.performLogin endpoint. The flaw allows authentication to proceed using an external Identity Provider (IdP) even after an administrator has disabled that IdP. The vulnerability arises because the system fails to properly enforce the disabled status of the IdP during the login process. An attacker who knows the alias of the disabled IdP can reuse a previously generated login request to bypass administrative restrictions and authenticate through the disabled provider. This bypass undermines the intended access control policies, potentially allowing unauthorized users to gain access to systems relying on Keycloak for authentication and identity federation. The vulnerability has a CVSS 3.1 base score of 8.1, indicating high severity, with an attack vector of network (remote exploitation), low attack complexity, requiring privileges (PR:L), no user interaction, and impacting confidentiality and integrity but not availability. Although no known exploits are reported in the wild, the vulnerability poses a significant risk due to its ability to circumvent administrative controls and the widespread use of Keycloak in enterprise identity management.

The vulnerability can lead to unauthorized access to systems and applications protected by Keycloak, as attackers can authenticate through disabled external IdPs. This compromises confidentiality by potentially exposing sensitive user data and internal resources. Integrity is also at risk because unauthorized users may gain elevated privileges or impersonate legitimate users. The availability of services is not directly impacted. Organizations relying on Keycloak for identity federation and single sign-on (SSO) are at risk of unauthorized access, which could lead to data breaches, lateral movement within networks, and compromise of critical systems. The ease of exploitation combined with the high impact on confidentiality and integrity makes this vulnerability particularly dangerous for enterprises with complex identity provider configurations and strict access control requirements.

Organizations should immediately verify if they are using Red Hat's build of Keycloak version 26.4 or similar versions and prioritize applying any available patches or updates from Red Hat addressing CVE-2026-3009. In the absence of patches, administrators should audit and temporarily disable or remove unused or untrusted Identity Providers to reduce attack surface. Implement additional monitoring and alerting on authentication attempts involving disabled IdPs to detect potential exploitation attempts. Restrict access to Keycloak administrative interfaces to trusted personnel and networks to prevent unauthorized changes to IdP configurations. Consider implementing compensating controls such as multi-factor authentication (MFA) for all federated login flows to reduce the risk of unauthorized access. Review and tighten logging and audit trails related to identity federation and authentication events to facilitate incident response. Finally, engage with Red Hat support or security advisories for any forthcoming patches or mitigation guidance.