Yonyou U8 Cloud contains an unauthenticated Java deserialization vulnerability in the nc.impl.pub.filesystem.FileManageServlet component that allows remote unauthenticated attackers to execute arbitrary OS commands by sending a serialized payload via POST request. Attackers can exploit the doAction method, which passes raw HTTP request body data directly to ObjectInputStream.readObject() without filtering, to achieve remote code execution. Exploitation evidence was first observed by the Shadowserver Foundation on 2025-02-13.