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CVE-2026-4634GHSA-H4WV-G838-66G3BIT-KEYCLOAK-2026-4634

Keycloak: keycloak: denial of service via excessive processing of openid connect scope parameters

Published
Last modified
published
Not listed in CISA KEV
Fix
Fixed in 26.5.7
None on Exploit-DB, Metasploit or GitHub
  • Exploitation: none
  • Automatable: yes
  • Technical impact: partial

Summary

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.

Timeline

  1. CVE published
  2. CISA SSVC assessment

    Exploitation: none · Automatable: yes · Technical impact: partial

  3. Record last updated

Affected versions

  • rhbk/keycloak-operator-bundle

    Version range not reported

  • rhbk/keycloak-rhel9

    Version range not reported

  • rhbk/keycloak-rhel9-operator

    Version range not reported

  • rhbk/keycloak-rhel9

    Version range not reported

  • rhbk/keycloak-operator-bundle

    Version range not reported

  • rhbk/keycloak-rhel9

    Version range not reported

  • rhbk/keycloak-rhel9-operator

    Version range not reported

  • rhbk/keycloak-rhel9

    Version range not reported

  • keycloak-services

    Version range not reported

  • rh-sso7-keycloak

    Version range not reported

  • rh-sso7-keycloak

    Version range not reported

  • rh-sso7-keycloak

    Version range not reported

  • rh-sso-7/sso76-openshift-rhel8

    Version range not reported

  • org.keycloak:keycloak-servicesMaven

    fixed in 26.5.7

References 11

access.redhat.com

bugzilla.redhat.com