An issue was discovered in GWTUpload's server/UploadServlet.java (the servlet for handling file upload) accepts a delay parameter that causes a thread to sleep. It can be abused to cause all of a server's threads to sleep, leading to denial of service.
There is an XSS vulnerability in GwtUpload in the file upload functionality. Someone can upload a file with a malicious filename, which contains JavaScript code, which would result in XSS. Cross-site scripting enables attackers to steal data, change the appearance of a website, and perform other malicious activities like phishing or drive-by hacking.