A critical remote code execution vulnerability has been discovered in Apache Struts, a popular open source framework for developing web applications in the Java programming language.  In the past, Apache Struts RCE vulnerabilities have been weaponized in less than 24 hours -- one of which resulted in the Equifax breach that totaled over $600 million in cost. 
It is recommended that you upgrade immediately if you are using Apache Struts, or contact your vendor if you manage vendor applications that rely on Apache Struts.
Attackers may be able to remotely execute arbitrary code against vulnerable Apache Struts installations. 
- Apache Struts 2.3 through 2.3.34
- Apache Struts 2.5 through 2.5.16
- Unsupported (end-of-life) versions of Apache Struts may also be vulnerable 
- Upgrade immediately to Apache Struts 2.3.35 or 2.5.17
- Contact your vendor for security patches if you manage vendor applications that utilize Apache Struts