The Apache Struts developers have released version 2.3.1.1 of their open source framework for Java-based web applications. The update fixes critical vulnerabilities in earlier versions(2.1.0 to 2.3.1).
The Vulnerabilities could be exploited by an attacker to circumvent restrictions by using dynamic method invocation (DMI) to inject and execute malicious Java code.
Updating to v2.3.1.1 fix the vulnerability. Alternatively, the security advisory provides instructions for changing a configuration file which mitigates the problem.
Here you can find more details about the latest release:
http://struts.apache.org/2.x/docs/version-notes-2311.html