Description

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.

Mitigation

We recommend upgrading to a version of this component that is not vulnerable to this specific issue.

Note: If this component is included as a bundled/transitive dependency of another component, there may not be an upgrade path. In this instance, we recommend contacting the maintainers who included the vulnerable package. Alternatively, we recommend investigating alternative components or a potential mitigating control.

Related links:

• http://web.nvd.nist.gov/view/vuln/detail?vulnId=CVE-2020-11996

• http://tomcat.apache.org/security-10.html#Fixed_in_Apache_Tomcat_10.0.0-M6

• http://tomcat.apache.org/security-8.html#Fixed_in_Apache_Tomcat_8.5.56

• http://tomcat.apache.org/security-9.html#Fixed_in_Apache_Tomcat_9.0.36

• https://lists.apache.org/thread.html/r5541ef6b6b68b49f76fc4c45695940116da2bcbe0312ef204a00a2e0%40%3Cannounce.tomcat.apache.org%3E