CVE-2026-23552 is a security vulnerability identified in the Apache Camel integration framework, specifically within its KeycloakSecurityPolicy component that manages JWT token validation. The vulnerability arises because the component fails to validate the 'iss' (issuer) claim in JWT tokens against the configured Keycloak realm. In a multi-tenant environment where multiple Keycloak realms exist, this flaw allows a token issued by one realm to be accepted by a policy configured for a different realm, effectively bypassing tenant isolation controls. This cross-realm token acceptance undermines the fundamental security guarantees of token-based authentication by allowing unauthorized access to resources intended for other tenants. The affected versions span from Apache Camel 4.15.0 up to but not including 4.18.0, with the issue resolved in version 4.18.0. The vulnerability is categorized under CWE-346, which pertains to origin validation errors, indicating a failure to properly verify the source of authentication tokens. Exploitation does not require user interaction but does require possession of a valid token from a different realm, which could be obtained through various means depending on the attacker's capabilities. No public exploits have been reported yet, but the potential for privilege escalation and data leakage in multi-tenant deployments is significant. The vulnerability impacts confidentiality and integrity by allowing unauthorized access and potentially unauthorized actions within affected systems.

The primary impact of CVE-2026-23552 is the breakdown of tenant isolation in environments using Apache Camel integrated with Keycloak for authentication. Organizations deploying multi-tenant applications relying on Keycloak realms to segregate users and permissions are at risk of unauthorized access across tenant boundaries. This can lead to data leakage, unauthorized data modification, and potential lateral movement within the affected infrastructure. The vulnerability compromises the integrity and confidentiality of authentication tokens, allowing attackers to impersonate users from other realms. This could result in exposure of sensitive information, violation of compliance requirements, and damage to organizational reputation. Additionally, the flaw could be leveraged to escalate privileges or bypass access controls, increasing the attack surface. Since Apache Camel is widely used in enterprise integration scenarios, the impact spans various industries including finance, healthcare, government, and cloud service providers. The absence of a known exploit in the wild reduces immediate risk but does not diminish the criticality of patching. Failure to address this vulnerability could lead to targeted attacks in environments where tenant isolation is crucial.

To mitigate CVE-2026-23552, organizations should immediately upgrade Apache Camel to version 4.18.0 or later, where the issuer validation flaw has been corrected. Until upgrading is possible, administrators should review and restrict access to Keycloak tokens, ensuring tokens are only accepted from trusted realms. Implement additional validation layers in the application logic to verify the 'iss' claim manually if feasible. Employ strict network segmentation and access controls to limit token exposure and reduce the risk of token theft or misuse. Monitor authentication logs for anomalies indicating cross-realm token usage. Conduct thorough security assessments of multi-tenant configurations to ensure tenant boundaries are enforced. Educate development and operations teams about the importance of validating JWT claims and the risks of origin validation errors. Consider deploying runtime application self-protection (RASP) or Web Application Firewalls (WAFs) with custom rules to detect and block suspicious token usage patterns. Finally, maintain up-to-date inventory of affected systems and integrate vulnerability scanning to detect outdated Apache Camel versions.