CVE-2026-19607

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.

Vulnerability class: Broken Authentication

CVSS v3 metric

CVSS v3 base score 5.3 (Medium). Vector: CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:N/I:N/A:L.

Weakness classification (CWE)

References

Frequently asked questions

What is CVE-2026-19607?
CVE-2026-19607 is a medium-severity vulnerability, classified under Improper Authentication. CVSS score: 5.3/10. Published 2026-09-16.
How severe is CVE-2026-19607?
Medium severity. CVSS v3 base score is 5.3 out of 10.