CVE-2026-19607

Keycloak-services: keycloak-services: broker-originated username collision causes account lockout

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.

Affected

Red Hat · Red Hat build of Keycloak 26.4 · Red Hat build of Keycloak 26.6

CVSS v3.1 REDHAT

5.3 MEDIUMCVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:N/I:N/A:L

EPSS

0.51% chance of exploitation in the next 30 days, 42nd percentile

Published

2026-09-16

Proof-of-concept exploits (1)

• 7Ragnarok7/CVE-2026-196071★ · 2026-10-16

References

• CVE Record
• NVD entry

Related

• CVE-2021-3754
• CVE-2024-37888