CVE-2026-19607
Medium
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.
SeverityMedium
CVSS5.3
Exploit probability—
ProductBuild Keycloak 26.4
PublishedSep 16, 2026
First seenSep 16, 2026
Weakness typeCWE-287Improper authentication
How to fix
Affected products
| Product | Affected versions | Fixed in |
|---|---|---|
| build_keycloak 26.4 | No range specified | — |
| build_keycloak 26.6 | No range specified | — |
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