CVE-2026-9798

Medium

Description

A flaw was found in Keycloak, an open-source identity and access management solution. When a user account is temporarily locked due to repeated failed login attempts, an attacker with valid client credentials can exploit the Client-Initiated Backchannel Authentication (CIBA) flow to bypass this brute-force protection. This allows continued authentication attempts and token issuance even when the account should be locked, potentially enabling further unauthorized access attempts.

SeverityMedium
CVSS4.3
Exploit probability—
ProductRedhat Build Of Keycloak
PublishedMay 28, 2026
First seenMay 28, 2026
Weakness typeCWE-305CWE-305

How to fix

Affected products

ProductAffected versionsFixed in
redhat build_of_keycloakNo range specified—
org.keycloak:keycloak-servicesMavenv ≤ 26.4.7, 26.5.0 ≤ v ≤ 26.6.4—

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