The REST Plugin in Apache Struts 2.1.x, 2.3.7 through 2.3.33 and 2.5 through 2.5.12 is using an outdated XStream library which is vulnerable and allow perform a DoS attack using malicious request with specially crafted XML payload.

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.

In Apache Struts 2.5 through 2.5.5, if an application allows entering a URL in a form field and the 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.

In Apache Struts 2.0.0 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.

If an application allows enter an 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. Solution is to upgrade to Apache Struts version 2.5.12.

When using a Spring AOP functionality to secure Struts actions it is possible to perform a DoS attack. Solution is to upgrade to Apache Struts version 2.5.12 or 2.3.33.