CVE-2026-18215: Red Hat Build Of Keycloak

High severity, CVSS 8.1. EPSS: 0.4% chance of exploitation in the next 30 days.

Keycloak provides a way to let users log in using Microsoft accounts while restricting access to a specific organization (tenant). A flaw was discovered where this restriction is ignored when using the token exchange feature. This means an attacker with a valid Microsoft token from a completely different organization could gain access to the Keycloak realm, potentially accessing sensitive data or performing unauthorized actions.

Affected products

• Red Hat Build Of Keycloak: affected versions not specified

Published 2026-07-31. Last modified 2026-09-16.