Traccar is an open source GPS tracking system. Versions prior to 6.0 are vulnerable to path traversal and unrestricted upload of file with dangerous type. Since the system allows registration by default, attackers can acquire ordinary user permissions by registering an account and exploit this vulnerability to upload files with the prefix "device." under any folder. Attackers can use this vulnerability for phishing, cross-site scripting attacks, and potentially execute arbitrary commands on the server. Version 6.0 contains a patch for the issue.