In Apache Struts 2.3.7 through 2.3.33 and 2.5 through 2.5.12, if an application allows entering a URL in a form field and built-in URLValidator is used, it is possible to prepare a special URL which will be used to overload server process when performing validation of the URL. NOTE: this vulnerability exists because of an incomplete fix for S2-047 / CVE-2017-7672.

The REST Plugin in Apache Struts 2.1.x, 2.3.7 through 2.3.33 and 2.5 through 2.5.12 is using an outdated XStream library which is vulnerable and allow perform a DoS attack using malicious request with specially crafted XML payload.

Apache Struts 2.x before 2.3.24.1 allows remote attackers to manipulate Struts internals, alter user sessions, or affect container settings via vectors involving a top object.