CVE-2026-4634 — Keycloak: keycloak: denial of service via excessive processing of openid connect scope parameters
A flaw was found in Keycloak. An unauthenticated attacker can exploit this vulnerability by sending a specially crafted POST request with an excessively long scope parameter to …
Published: 2026-04-02 · CVSS: 7.5 · CVSS 3.1
A flaw was found in Keycloak. An unauthenticated attacker can exploit this vulnerability by sending a specially crafted POST request with an excessively long scope parameter to the OpenID Connect (OIDC) token endpoint. This leads to high resource consumption and prolonged processing times, ultimately resulting in a Denial of Service (DoS) for the Keycloak server.
Source: CVE Program · Revision 8b16575c39f1e1810c5e863010da073d2d3285e7