In Apache Struts 2.0.1 through 2.3.33 and 2.5 through 2.5.10.1, using an unintentional expression in a Freemarker tag instead of string literals can lead to a RCE attack.
www.arubanetworks.com/assets/alert/ARUBA-PSA-2017-003.txt
www.oracle.com/technetwork/security-advisory/alert-cve-2017-9805-3889403.html
github.com/apache/struts
github.com/apache/struts/commit/2306f5f7fad7f0157f216f34331238feb0539fa
github.com/apache/struts/commit/637ad1c3707266c33daabb18d7754e795e6681f
kb.netapp.com/support/s/article/ka51A000000CgttQAC/NTAP-20170911-0001
nvd.nist.gov/vuln/detail/CVE-2017-12611
struts.apache.org/docs/s2-053.html
web.archive.org/web/20170923161654/www.securityfocus.com/bid/100829