The REST plugin in Apache Struts 2 2.3.19 through 2.3.28.1 allows remote attackers to execute arbitrary code via a crafted expression.
https://struts.apache.org/docs/s2-037.html
https://bugzilla.redhat.com/show_bug.cgi?id=1348238
http://www.securityfocus.com/bid/91275
http://www.oracle.com/technetwork/security-advisory/cpujul2017-3236622.html