CVE-2026-19607
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.
- Published Sep 16, 2026
- CVSS 5.3 medium
- 0.5% chance of exploitation in the next 30 days (EPSS)
- A fix is available