CVE-2026-18209 Keycloak-services: keycloak-services: oidc redirect_uri fragment bypass in http parameter pollution check

A flaw was found in the keycloak-services component of Keycloak, which handles OpenID Connect OIDC authentication flows. The issue occurs because the security check designed to prevent HTTP parameter pollution only inspects the query portion of a redirect URL and ignores the fragment portion. Whe...