Launch Week Day 1: Announcing Security Design Review
HIGH 7.5 Maven

Keycloak: Application-Level DoS via Scope Processing

GHSA-h4wv-g838-66g3 · CVE-2026-4634

Published · Modified

Description

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.

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