The defaults settings for the CORS filter provided in Apache Tomcat are insecure and enable 'supportsCredentials' for all origins. It is expected that users of the CORS filter will have configured it appropriately for their environment rather than using it in the default configuration. Therefore, it is expected that most users will not be impacted by this issue.An improper handing of overflow in the UTF-8 decoder with supplementary characters can lead to an infinite loop in the decoder causing a Denial of Service. Versions Affected: Apache Tomcat 8.5.0 to 8.5.30. The host name verification when using TLS with the WebSocket client was missing. It is now enabled by default. Versions Affected: Apache Tomcat 8.5.0 to 8.5.31.A bug in the tracking of connection closures can lead to reuse of user sessions in a new connection. Versions Affected: Apache Tomcat 8.5.5 to 8.5.31.