CVE-2026-3009 is a security vulnerability identified in the Red Hat Build of Keycloak, specifically in the IdentityBrokerService.performLogin endpoint. Keycloak is an open-source identity and access management solution widely used for single sign-on (SSO) and identity federation. The flaw allows an attacker to bypass administrative restrictions that disable an external Identity Provider (IdP). Normally, when an administrator disables an IdP, authentication requests through that provider should be rejected. However, due to improper authorization checks, an attacker who knows the alias of the disabled IdP can reuse a previously generated login request to authenticate successfully. This bypass undermines the access control mechanisms intended to prevent unauthorized authentication via disabled IdPs. The vulnerability does not require user interaction and can be exploited remotely over the network with low privileges, making it easier to exploit. The flaw impacts the confidentiality and integrity of authentication processes by allowing unauthorized access without alerting administrators. Although no known exploits are reported in the wild yet, the high CVSS score (8.1) indicates a significant risk. The vulnerability affects all deployments of Red Hat Build of Keycloak that use external IdPs and rely on administrative disabling of these providers for access control. Since Keycloak is widely used in enterprise environments for identity federation, this vulnerability poses a substantial risk to organizations relying on it for secure authentication.

The impact of CVE-2026-3009 is significant for organizations using Red Hat Build of Keycloak for identity federation and single sign-on. Unauthorized authentication through a disabled IdP can lead to unauthorized access to sensitive systems and data, compromising confidentiality and integrity. Attackers can bypass administrative controls designed to restrict access, potentially gaining persistent footholds in enterprise environments. This can facilitate lateral movement, data exfiltration, and privilege escalation within affected networks. The vulnerability does not affect availability directly but can severely undermine trust in the authentication infrastructure. Organizations in sectors such as finance, healthcare, government, and technology that rely on Keycloak for secure identity management are particularly at risk. The ease of exploitation and lack of user interaction required increase the likelihood of exploitation attempts once public details become widespread. The absence of known exploits in the wild currently provides a window for mitigation before active attacks emerge.

Organizations should prioritize applying official patches or updates from Red Hat as soon as they become available to address CVE-2026-3009. In the interim, administrators should audit their Keycloak configurations to identify any disabled IdPs and verify that no legacy or cached login requests can be reused. Implement strict monitoring and logging of authentication attempts, focusing on unusual reuse of login requests or authentication from disabled IdPs. Consider temporarily disabling or removing unused or legacy IdPs to reduce attack surface. Employ network-level controls such as Web Application Firewalls (WAFs) to detect and block suspicious authentication requests. Review and tighten access controls around Keycloak administrative functions to prevent unauthorized changes to IdP configurations. Educate security teams about this vulnerability to ensure rapid detection and response to potential exploitation attempts. Finally, maintain an incident response plan tailored to identity management compromise scenarios.