CVE-2026-18208

Name of the Vulnerable Software and Affected Versions keycloak-services (affected versions not specified)

Description A flaw exists in the OIDC token introspection endpoint of the keycloak-services component. The issue occurs when a confidential client, configured to receive signed JWT (JSON Web Token) introspection responses, attempts to introspect a token issued for a different audience. While the endpoint correctly identifies the token as inactive for that client, it still returns the full set of token claims within a signed JWT field. This allows an unauthorized client to bypass audience-based restrictions and access sensitive information contained in the token.

Recommendations At the moment, there is no information about a newer version that contains a fix for this vulnerability.