This update for tomcat to version 9.0.21 fixes the following issues: Security issues fixed: - CVE-2019-0199: Fixed a denial of service in the HTTP/2 implementation related to streams with excessive numbers of SETTINGS frames . - CVE-2019-0221: Fixed a cross site scripting vulnerability with the SSI printenv command . - CVE-2019-10072: Fixed incomplete patch for CVE-2019-0199 . Please also see