Definition: log4j

A module added into many Java applications that provides a logging function. The log4j code keeps track of the program's instruction execution for debugging purposes when problems arise later on.

Used almost everywhere, it became a nightmare in 2021 when it was found to execute any code given it with no verification whatsoever. In other words, a direct order to execute malware with no restriction. The tech world was horrified because more than 10 billion devices were estimated to be at risk and developers have been in a frenzy to fix it. Stay tuned.