Adam Thomas

**Name of the Vulnerable Software and Affected Versions** Apache Tomcat versions 8.5.0 through 8.5.77 Apache Tomcat versions 9.0.0-M1 through 9.0.60 Apache Tomcat versions 10.0.0-M1 through 10.0.18 Apache Tomcat versions 10.1.0 through 10.1.0-M12 **Description** The simplified implementation of blocking reads and writes introduced in Tomcat 10 and back-ported to Tomcat 9.0.47 onwards exposed a long standing concurrency bug that could cause client connections to share an `Http11Processor` instance resulting in responses, or part responses, to be received by the wrong client. **Recommendations** For Apache Tomcat versions 8.5.0 through 8.5.77, update to a version outside of this range to resolve the issue. For Apache Tomcat versions 9.0.0-M1 through 9.0.60, update to a version outside of this range to resolve the issue. For Apache Tomcat versions 10.0.0-M1 through 10.0.18, update to a version outside of this range to resolve the issue. For Apache Tomcat versions 10.1.0 through 10.1.0-M12, update to a version outside of this range to resolve the issue. As a temporary workaround, consider restricting access to the `Http11Processor` instance to minimize the risk of exploitation.