HIGH 7.5 Maven
Keycloak: Application-Level DoS via Scope Processing
GHSA-h4wv-g838-66g3 · CVE-2026-4634
Published · Modified
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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.
References
- ADVISORY https://nvd.nist.gov/vuln/detail/CVE-2026-4634
- WEB https://github.com/keycloak/keycloak/issues/47716
- WEB https://github.com/keycloak/keycloak/commit/b455ee4f28abb6f2120aff72fd179589cc5267a0
- WEB https://access.redhat.com/errata/RHSA-2026:6475
- WEB https://access.redhat.com/errata/RHSA-2026:6476
- WEB https://access.redhat.com/errata/RHSA-2026:6477
- WEB https://access.redhat.com/errata/RHSA-2026:6478
- WEB https://access.redhat.com/security/cve/CVE-2026-4634
- WEB https://bugzilla.redhat.com/show_bug.cgi?id=2450250
- PACKAGE https://github.com/keycloak/keycloak
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