Apache Struts Remote Code Execution Vulnerability

Summary

Apache Struts contains a vulnerability that allows for remote code execution under two circumstances. One, where the alwaysSelectFullNamespace option is true and the value isn't set for a result defined in underlying configurations and in same time, its upper package configuration have no or wildcard namespace. Or, using URL tag which doesn't have value and action set and in same time, its upper package configuration have no or wildcard namespace.