zhangyanbo2007 youkefu MediaController.java upload unrestricted upload

A vulnerability, which was classified as critical, was found in zhangyanbo2007 youkefu up to 4.2.0. Affected is the function Upload of the file \youkefu-master\src\main\java\com\ukefu\webim\web\handler\resource\MediaController.java. The manipulation of the argument imgFile leads to unrestricted upload. It is possible to launch the attack remotely. The exploit has been disclosed to the public and may be used.