CVE-2026-16103

Name of the Vulnerable Software and Affected Versions Keycloak (affected versions not specified)

Description A flaw exists in the keycloak-services component. The token redemption handler for Client-Initiated Backchannel Authentication (CIBA) lacks brute-force protection checks. This allows an attacker possessing valid client credentials to obtain access and refresh tokens for a user account that is currently locked due to brute-force protection, as long as the authentication request was initiated before the lockout and received user approval.

Recommendations At the moment, there is no information about a newer version that contains a fix for this vulnerability.