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3.4 Low

CVE-2026-18209 A flaw was found in the keycloak-services component of Keycloak, which handles OpenID Connect (OIDC) authentication…

Description

A flaw was found in the keycloak-services component of Keycloak, which handles OpenID Connect (OIDC) authentication flows. The issue occurs because the security check designed to prevent HTTP parameter pollution only inspects the query portion of a redirect URL and ignores the fragment portion. When a client is configured with a wildcard redirect URI, an attacker can use this to inject duplicate security parameters into the login response. If a client application is not configured correctly, it might trust the attacker's injected data instead of the real security information from Keycloak, leading to session fixation or account confusion.

Affected products and versions

Product Affected versions Fixed in
Red Hat Build of Keycloak Versions not published
Red Hat Data Grid 8 Versions not published
Red Hat JBoss Enterprise Application Platform Expansion Pack Versions not published
Red Hat Single Sign-On 7 Versions not published
Red Hat build of Keycloak 26.6 26.6 earliest → < 26.6-20 26.6-20
Red Hat build of Keycloak 26.6.7 Versions not published

References

Timeline

  1. Published
  2. Last modified

Other CVEs of Red Hat Build of Keycloak

The 266 CVEs of Red Hat Build of Keycloak →
CVE-2026-97847 Keycloak-services: keycloak-services: client manager can substitute sessionless token principal via hardcoded-claim mappers to obtain realm administrator authority 7.1 High CVE-2026-97175 Keycloak-services: keycloak-services: unverified idp email auto-linking enables account takeover 8.8 High CVE-2026-97174 Keycloak-services: keycloak-services: ciba sub parameter injection causes attacker authentication to issue victim tokens 6.8 Medium CVE-2026-96453 Org.keycloak/keycloak-admin-cli: keycloak-admin-cli: kcadm custom truststore accepts arbitrary self-signed certificates 8.0 High
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