Unrestricted file upload

An issue was discovered in osTicket before 1.10.7 and 1.12.x before 1.12.1. The Ticket creation form allows users to upload files along with queries. It was found that the file-upload functionality has fewer (or no) mitigations implemented for file content checks; also, the output is not handled properly, causing persistent XSS that leads to cookie stealing or malicious actions. For example, a non-agent user can upload a .html file, and Content-Disposition will be set to inline instead of attachment.