Org.keycloak/keycloak-services: session fixation in oidc login flow that can lead to account takeover

Summary

A session fixation vulnerability was found in Keycloak's login-actions endpoints. An unauthenticated attacker could exploit this flaw by pre-creating an authentication session and tricking a victim into visiting a maliciously crafted link. By leveraging the /login-actions/restart endpoint—which processes session handles without adequate CSRF protection or cookie ownership validation—an attacker can reset the authentication flow state. This causes Single Sign-On (SSO) to authenticate the victim transparently upon clicking the link, allowing the attacker to hijack the required-action form without needing the victim's credentials. A successful exploit could lead to complete account takeover, including highly privileged administrative accounts.

Timeline

1. May 19, 2026, 11:01 AM UTCCVE published
2. May 19, 2026, 1:40 PM UTCCISA SSVC assessment

   Exploitation: none · Automatable: no · Technical impact: total

3. Oct 6, 2026, 4:59 PM UTCRecord 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-operator

  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-operator

  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 26.6.2

References 11