A specially crafted sequence of HTTP/2 requests sent to Apache Tomcat 10.0.0-M1 to 10.0.0-M5, 9.0.0.M1 to 9.0.35 and 8.5.0 to 8.5.55 could trigger high CPU usage for several seconds. If a sufficient number of such requests were made on concurrent HTTP/2 connections, the server could become unresponsive.
https://www.oracle.com/security-alerts/cpuoct2020.html
https://www.oracle.com/security-alerts/cpujan2021.html
https://www.debian.org/security/2020/dsa-4727
https://usn.ubuntu.com/4596-1/
https://security.netapp.com/advisory/ntap-20200709-0002/
https://lists.debian.org/debian-lts-announce/2020/07/msg00010.html
http://lists.opensuse.org/opensuse-security-announce/2020-07/msg00072.html
http://lists.opensuse.org/opensuse-security-announce/2020-07/msg00064.html