CVE-2025-13467 is a deserialization vulnerability found in the LDAP User Federation provider component of the Red Hat build of Keycloak version 26.2. The flaw arises because the system deserializes Java objects received from an LDAP server configuration without sufficient validation, allowing an authenticated realm administrator to supply malicious serialized data. This can lead to execution of arbitrary code or manipulation of internal state, compromising confidentiality and integrity of the authentication system. The vulnerability requires the attacker to have realm administrator privileges, which limits the attack surface but still poses a significant risk since such privileges allow broad control over identity management. The vulnerability does not require user interaction and can be exploited remotely over the network (AV:N). The CVSS score is 5.5 (medium), reflecting the moderate impact and the requirement for high privileges. No patches or exploits are currently publicly available, but the flaw is published and should be addressed promptly. The vulnerability affects the deserialization process in Java, a common source of security issues due to unsafe handling of serialized data. Since Keycloak is widely used for single sign-on and identity federation, exploitation could disrupt authentication services and expose sensitive user information.

For European organizations, the impact of this vulnerability can be significant, especially for those relying on Keycloak 26.2 for identity and access management in critical infrastructure, government services, or large enterprises. An attacker with realm admin privileges could manipulate authentication flows, potentially gaining unauthorized access to sensitive applications or data. The compromise of confidentiality and integrity could lead to data breaches or unauthorized privilege escalation within the organization. While availability is not directly impacted, the disruption of authentication services could indirectly affect business operations. Given the central role of identity providers in security architectures, exploitation could have cascading effects across multiple systems. Organizations in sectors such as finance, healthcare, and public administration, which have stringent regulatory requirements under GDPR and other frameworks, may face compliance risks and reputational damage if this vulnerability is exploited.

To mitigate this vulnerability, organizations should immediately review and restrict realm administrator privileges to trusted personnel only, minimizing the risk of malicious LDAP configurations. Applying security patches from Red Hat as soon as they become available is critical. In the absence of patches, organizations should consider disabling or limiting the use of the LDAP User Federation provider if feasible. Conduct thorough audits of LDAP server configurations to detect any unauthorized or suspicious entries. Implement network segmentation and monitoring to detect anomalous LDAP traffic patterns. Employ Java deserialization security best practices, such as using safe deserialization libraries or applying deserialization filters to prevent untrusted data processing. Additionally, enhance logging and alerting around administrative actions in Keycloak to quickly identify potential exploitation attempts. Regularly update Keycloak and dependent components to the latest secure versions.