In Apache Struts 2.3.x before 2.3.31, and 2.5.x before 2.5.5, it is possible to prepare a special URL which will be used for path traversal and execution of arbitrary code on server side. This vulnerability is only exploitable when using the Struts 2 Convention plugin in conjunction with Apache Struts.

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.

Apache Struts 2 before 2.3.29 and 2.5.x before 2.5.1 allow attackers to have unspecified impact via vectors related to improper action name clean up.

It was found that it is possible to pass a malicious expression which can be used to execute arbitrary code on server side when using the REST Plugin.

External References:

https://struts.apache.org/docs/s2-037.html

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.

XSLTResult allows for the location of a stylesheet being passed as a request parameter. In some circumstances this can be used to inject remotely executable code.

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 method: prefix, related to chained expressions.