Apache Struts 2.0.0 to 2.5.20 forced double OGNL evaluation, when evaluated on raw user input in tag attributes, may lead to remote code execution.
Published: 2020-08-14
Apache published two security bulletins to address a potential remote code execution vulnerability and a denial of service vulnerability. Public proof of concept code is available. Background On August 13, Apache published security bulletins to address two vulnerabilities in Apache Struts version 2. Apache Struts is an open source model-view-controller (MVC) framework used to create Java web applications.
https://www.oracle.com/security-alerts/cpuoct2021.html