Apache Struts versions 2.3 to 2.3.34 and 2.5 to 2.5.16 suffer from possible Remote Code Execution when alwaysSelectFullNamespace is true (either by user or a plugin like Convention Plugin) and then: results are used with no namespace and in same time, its upper package have no or wildcard namespace and similar to results, same possibility when using url tag which doesn’t have value and action set and in same time, its upper package have no or wildcard namespace. **Recent assessments:** **zeroSteiner** at April 14, 2020 6:33pm UTC reported: This vulnerability exists within the Apache Struts OGNL method dispatch routine. An attacker can submit a specially crafted HTTP request to a vulnerable web server. Specifically an attacker can taint the `name` parameter passed to [`OgnlUtil::getValue()`](<https://lgtm.com/projects/g/apache/struts/snapshot/02518d8149ff0b60863b4012cd3268cf0f2942b7/files/core/src/main/java/com/opensymphony/xwork2/ognl/OgnlUtil.java?sort=name&dir=ASC&mode=heatmap#L301>). Exploitation of this vulnerability would lead to code execution within the context of the Java process powering the server. An indicator of compromise will be present in the logs at the `DEBUG` level. This IOC will look like a malformed value in the `Executing action method =` message. The default configuration is not vulnerable. The `alwaysSelectFullNamespace` option must be enabled. This can be done by adding `<constant name="struts.mapper.alwaysSelectFullNamespace" value="true" />` to the `struts.xml` configuration file. Assessed Attacker Value: 4 Assessed Attacker Value: 4Assessed Attacker Value: 5