Medium [CVE-2026-88770] Device Authorization Grant issues tokens to brute-force-locked accounts

A flaw was found in the Device Authorization Grant flow of Keycloak, an identity and access management solution. The issue occurs because the token redemption process fails to check if a user account is currently locked due to brute-force protection.

If an attacker has an active session for a locked account, they can complete the device login process and receive new security tokens. This allows the attacker to maintain access to the account even when it should be temporarily disabled to prevent unauthorized entry.

The Red Hat Product Security team has assessed the severity of this vulnerability as Moderate, given that exploitation requires the attacker to hold a valid SSO browser session for the target account established prior to the lockout.

Successful exploitation allows an attacker to bypass brute-force protection policies and obtain valid tokens for a locked account. The vulnerability's root cause is the missing brute-force status check in the Device Authorization Grant token redemption code path.

Weakness: CWE-307. Affected Red Hat products: Red Hat Build of Keycloak; Red Hat Single Sign-On 7.

Red Hat does not currently list a fixing RHSA for this CVE.