CVE-2025-1391: 
Java vulnerability analysis and mitigation

A vulnerability (CVE-2025-1391) was discovered in the Keycloak organization feature, specifically affecting the Organization Mapper component. The flaw was disclosed on February 17, 2025, impacting Keycloak services and allowing incorrect assignment of organization claims to users based on email/username patterns (Red Hat Bugzilla, NVD).

The vulnerability stems from improper authorization in the Keycloak Organization Mapper, which incorrectly validates user-to-organization mappings based on email or username patterns. The issue manifests at the token claim level, meaning while users aren't actually added to organizations, they may appear as members in applications that rely on these claims (Red Hat Bugzilla).

The vulnerability affects token claims, potentially allowing unauthorized users to appear as members of organizations they shouldn't have access to. This impact is particularly significant in environments where self-registration is enabled and unrestricted, as it could allow attackers to exploit naming patterns to gain unauthorized access to organization-specific resources (Red Hat Bugzilla).

Red Hat has addressed this vulnerability by releasing security updates in Red Hat build of Keycloak 26.0.10. Administrators can mitigate the risk by restricting user registration and implementing strict validation mechanisms. The fix is available through security advisories RHSA-2025:2544 and RHSA-2025:2545 (Red Hat Advisory, Red Hat Advisory 2).