Changjetong T+ versions up to and including 16.x contain a .NET deserialization vulnerability in an AjaxPro endpoint that can lead to remote code execution. A remote attacker can send a crafted request to /tplus/ajaxpro/Ufida.T.CodeBehind._PriorityLevel,App_Code.ashx?method=GetStoreWarehouseByStore with a malicious JSON body that leverages deserialization of attacker-controlled .NET types to invoke arbitrary methods such as System.Diagnostics.Process.Start. This can result in execution of arbitrary commands in the context of the T+ application service account. Exploitation evidence was observed by the Shadowserver Foundation on 2023-08-19 (UTC).