A flaw was found in the first-broker-login flow of the keycloak-services component. This component handles the initial authentication and account linking when a user logs in via an external identity provider. The issue allows an attacker to register a matching username on an external provider to trigger a collision in Keycloak, which results in the legitimate user being locked out of their account.

Project Subscriptions

Vendors Products
Build Keycloak Subscribe
Red Hat Single Sign On Subscribe
Advisories

No advisories yet.

Fixes

Solution

No solution given by the 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.

History

Wed, 16 Sep 2026 19:30:00 +0000

Type Values Removed Values Added
Metrics ssvc

{'options': {'Automatable': 'yes', 'Exploitation': 'none', 'Technical Impact': 'partial'}, 'version': '2.0.3'}


Wed, 16 Sep 2026 16:30:00 +0000

Type Values Removed Values Added
First Time appeared Redhat red Hat Single Sign On
CPEs cpe:/a:redhat:red_hat_single_sign_on:7
Vendors & Products Redhat red Hat Single Sign On

Wed, 16 Sep 2026 16:00:00 +0000

Type Values Removed Values Added
Description A flaw was found in the first-broker-login flow of the keycloak-services component. This component handles the initial authentication and account linking when a user logs in via an external identity provider. The issue allows an attacker to register a matching username on an external provider to trigger a collision in Keycloak, which results in the legitimate user being locked out of their account.
Title Keycloak-services: keycloak-services: broker-originated username collision causes account lockout
First Time appeared Redhat
Redhat build Keycloak
Weaknesses CWE-287
CPEs cpe:/a:redhat:build_keycloak:26.4::el9
cpe:/a:redhat:build_keycloak:26.6::el9
Vendors & Products Redhat
Redhat build Keycloak
References
Metrics cvssV3_1

{'score': 5.3, 'vector': 'CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:N/I:N/A:L'}


Projects

Sign in to view the affected projects.

cve-icon MITRE

Status: PUBLISHED

Assigner: redhat

Published:

Updated: 2026-09-16T18:35:08.909Z

Reserved: 2026-08-12T08:42:14.784Z

Link: CVE-2026-19607

cve-icon Vulnrichment

Updated: 2026-09-16T18:25:15.167Z

cve-icon NVD

Status : Awaiting Analysis

Published: 2026-09-16T16:17:06.607

Modified: 2026-09-16T19:42:43.623

Link: CVE-2026-19607

cve-icon Redhat

No data.

cve-icon OpenCVE Enrichment

No data.

Weaknesses