CVE-2026-9798

[CVE catalog]

Severity

Medium · CVSS 4.3CVSS:3.1/AV:N/AC:L/PR:N/UI:R/S:U/C:L/I:N/A:N

Published

May 27, 2026, 10:00:00 PM UTC

Source

[NVD] · [CVE record]

EPSS

0.38% · Oct 25, 2026

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. keycloak: Keycloak: Brute-force protection bypass in CIBA flow This flaw in Keycloak's Client-Initiated Backchannel Authentication (CIBA) flow is rated as Low impact. The vulnerability allows bypassing brute-force protection when a user account is locked, but only if CIBA is explicitly enabled and configured (non-default), and the user approves the authentication request on their device. This significantly limits the attack surface in typical Red Hat deployments where CIBA is not enabled by default. The CVSS score(s) listed for this vulnerability do not reflect the associated product's status, and are included for informational purposes to better understand the severity of this vulnerability.