CVE-2026-4633

Keycloak: keycloak: user enumeration via differential error messages

Published Mar 23, 2026 CVSS 3.1 · 3.7 Low EPSS < 1% KEV · Not listed
Description
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.

Remediation

Vendor Workaround

Mitigation for this issue is either not available or the currently available options do not meet the Red Hat Product Security criteria comprising ease of use and deployment, applicability to widespread installation base or stability.

Tracking

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Advisories

Source ID Title
Github GHSA Github GHSA GHSA-rhgq-f8x5-j2jc Keycloak's identity-first login flow exposes user information
History
Type Values Removed Values Added
CPEs cpe:/a:redhat:build_keycloak:26.4::el9
References
Type Values Removed Values Added
First Time appeared Redhat build Of Keycloak
CPEs cpe:2.3:a:redhat:build_of_keycloak:-:*:*:*:-:*:*:*
Vendors & Products Redhat build Of Keycloak
Type Values Removed Values Added
Metrics ssvc

{'options': {'Automatable': 'no', 'Exploitation': 'none', 'Technical Impact': 'partial'}, 'version': '2.0.3'}

Type Values Removed Values Added
Description 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.
Title Keycloak: keycloak: user enumeration via differential error messages
First Time appeared Redhat
Redhat build Keycloak
Weaknesses CWE-209
CPEs cpe:/a:redhat:build_keycloak:
Vendors & Products Redhat
Redhat build Keycloak
References
Metrics cvssV3_1

{'score': 3.7, 'vector': 'CVSS:3.1/AV:N/AC:H/PR:N/UI:N/S:U/C:L/I:N/A:N'}

Weaknesses

Sources

Status
PUBLISHED
Assigner
redhat
Published
Updated
Oct 22, 2026, 9:17 PM
Reserved
Mar 23, 2026, 8:36 AM
Status
Modified
Published
Mar 23, 2026, 11:16 AM
Modified
Oct 22, 2026, 10:18 PM