Log for J Is a Vulnorability in the Log for J Library.

Vulnerability allows people from the outside, filling in a web formed, to execute code on a server that they don't own. The easiest way to make something log is a websr. Wee it, tipe in a yu or el and then stick whatever you want after it. If someone on the outside can cause an unpatched log for jay server to write a log entry the outside person's composition, then the outside person can execute urbitory code.