This update for tomcat fixes the following issues: CVE-2020-9484 Apache Tomcat Remote Code Execution via session persistence If an attacker was able to control the contents and name of a file on a server configured to use the PersistenceManager, then the attacker could have triggered a remote code execution via deserialization of the file under their control. CVE-2019-12418 Local privilege escalation by manipulating the RMI registry and performing a man-in-the-middle attack When Tomcat is configured with the JMX Remote Lifecycle Listener, a local attacker without access to the Tomcat process or configuration files was able to manipulate the RMI registry to perform a man-in-the-middle attack to capture user names and passwords used to access the JMX interface. The attacker could then use these credentials to access the JMX interface and gain complete control over the Tomcat instance. CVE-2019-0221 The SSI printenv command echoed user provided data without escaping, which made it vulnerable to XSS. CVE-2019-17563 When using FORM authentication there was a narrow window where an attacker could perform a session fixation attack. CVE-2019-17569 Invalid Transfer-Encoding headers were incorrectly processed leading to a possibility of HTTP Request Smuggling if Tomcat was located behind a reverse proxy that incorrectly handled the invalid Transfer-Encoding header.