Apache Struts 2 is an open-source web application framework for developing Java EE web applications. It uses and extends the Java Servlet API to encourage developers to adopt a model–view–controller MVC architecture. The WebWork framework spun off from Apache Struts 1 aiming to offer enhancements and refinements while retaining the same general architecture of the original Struts framework. In December 2005, it was announced that WebWork 2.2 was adopted as Apache Struts 2, which reached its first full release in February 2007.
Struts 2 has a history of critical security bugs, many tied to its use of OGNL technology; some vulnerabilities can lead to arbitrary code execution. In October 2017, it was reported that failure by Equifax to address a Struts 2 vulnerability advised in March 2017 was later exploited in the data breach that was disclosed by Equifax in September 2017.