The Apache Software Foundation has released an advisory to address a vulnerable commons-fileupload library used in Apache Struts versions 2.3.36 and prior. A remote attacker could exploit this vulnerability to take control of an affected system. Struts versions from 2.5.12 are not affected.
By exploiting this vulnerability, it is possible to perform a Remote Code Execution (RCE) attack.
Upgrade to the latest released version of Commons FileUpload library, which is currently 1.3.3. Deployed applications can be hardened by replacing the commons-fileupload jar file in WEB-INF/lib with the fixed jar. For Maven based Struts 2 projects, the following dependency needs to be added: