The refresh token grant type in WSO2 products fails to re-validate account status before issuing new access tokens. This weakness allows an attacker to obtain valid access tokens for user accounts even after they have been blocked by the user store, bypassing account lockout mechanisms. This vulnerability can lead to unauthorized access to user accounts and their associated resources. Attackers can leverage this to perform actions on behalf of blocked users, potentially leading to privilege escalation or data exfiltration depending on the permissions of the compromised account.