CVE-2026-107623A flaw was found in the OIDC Dynamic Client Registration (DCR) component of Keycloak. A bug in the response serialization causes the backchannel logout offline token revocation setting to be omitted from responses. When a client performs a standard update, this missing information causes the setting to be silently disabled. As a result, offline tokens may remain valid even after a user session is terminated via backchannel logout.