OpenEMR is a free and open source electronic health records and medical practice management application. Prior to 8.0.0.2, the module ACL function "AclMain::zhAclCheck()" only checks for the presence of any "allow" (user or group). It never checks for explicit "deny" (allowed=0). As a result, administrators cannot revoke access by setting a user or group to "deny"; if the user is in a group that has "allow," access is granted regardless of explicit denies. Version 8.0.0.2 fixes the issue.