An access permission override in Apache Struts 2.0.0 to 2.5.20 may cause a Denial of Service when performing a file upload.
https://www.oracle.com/security-alerts/cpuoct2021.html
https://www.oracle.com/security-alerts/cpujan2021.html
https://www.oracle.com/security-alerts/cpuApr2021.html