Critical [CVE-2026-18963] Unauthenticated account takeover via reset-credentials flow bypass

A flaw was found in the reset-credentials flow of the keycloak-services component, which is the core engine for identity and access management in Red Hat Build of Keycloak. The issue allows an unauthenticated attacker to force the password reset process for any user without needing to click the required email verification link.

This can result in the attacker gaining full control over target user accounts by directly setting new credentials. The Red Hat Product Security team has assessed the severity of this vulnerability as Critical, given that it can be exploited by an unauthenticated remote attacker without any user interaction.

Successful exploitation allows an attacker to gain full access to any user account by bypassing the email verification step in the password recovery process. The vulnerability's root cause is improper state validation within the reset-credentials authentication flow.

Weakness: CWE-640. Affected Red Hat products: Red Hat build of Keycloak 26.4; Red Hat build of Keycloak 26.4.15; Red Hat build of Keycloak 26.6; Red Hat build of Keycloak 26.6.6.

Red Hat lists Red Hat JBoss Enterprise Application Platform Expansion Pack; Red Hat Single Sign-On 7 as not affected. Red Hat fixing advisory: RHSA-2026:56519, RHSA-2026:56520, RHSA-2026:56524, RHSA-2026:56523.