CVE-2026-4633: Keycloak's identity-first login flow exposes user information
(updated )
A flaw was found in Keycloak. A remote attacker can exploit differential error messages during the identity-first login flow when Organizations are enabled. This vulnerability allows an attacker to determine the existence of users, leading to information disclosure through user enumeration.
References
- access.redhat.com/errata/RHSA-2026:19596
- access.redhat.com/security/cve/CVE-2026-4633
- bugzilla.redhat.com/show_bug.cgi?id=2450247
- github.com/advisories/GHSA-rhgq-f8x5-j2jc
- github.com/keycloak/keycloak/commit/b137016cc6dcfd9f59b2aa2e6d73af8b0ebf7c6e
- github.com/keycloak/keycloak/commit/b4558a874fa79341404ae4d2d8f240f22bfed340
- github.com/keycloak/keycloak/issues/47619
- github.com/keycloak/keycloak/pull/47635
- nvd.nist.gov/vuln/detail/CVE-2026-4633
Code Behaviors & Features
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