A -1 is often used to see if someone isn't sanitizing input correctly, as under certain circumstances it generates a numerical underflow. I see people looking f

A -1 is often used to see if someone isn't sanitizing input correctly, as under certain circumstances it generates a numerical underflow. I see people looking for vulnerabilities feeding -1 to the HTML content-length header all the time. If it's generating errors in your app, perhaps you need to look at you're handling that field.