Apache Struts 2.3.19 to 2.3.20.2, 2.3.21 to 2.3.24.1, and 2.3.25 to 2.3.28, when Dynamic Method Invocation is enabled, allow remote attackers to execute arbitrary code via vectors related to an !
(exclamation mark) operator to the REST Plugin.
struts.apache.org/docs/s2-033.html
www-01.ibm.com/support/docview.wss?uid=swg21987854
github.com/apache/struts
github.com/apache/struts/commit/6bd694b7980494c12d49ca1bf39f12aec3e03e2f
nvd.nist.gov/vuln/detail/CVE-2016-3087
web.archive.org/web/20160616082237/www.securitytracker.com/id/1036017
web.archive.org/web/20160728170709/www.securityfocus.com/bid/90960
www.exploit-db.com/exploits/39919