Description
There is an XSS (cross-site scripting) vulnerability in GwtUpload 1.0.3 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.
Remediation
References
https://github.com/manolo/gwtupload/issues/32
https://www.coresecurity.com/advisories/gwtupload-xss-file-upload-functionality