Description

The HTTP/2 implementation in Apache Tomcat 9.0.0.M1 to 9.0.14 and 8.5.0 to 8.5.37 accepted streams with excessive numbers of SETTINGS frames and also permitted clients to keep streams open without reading/writing request/response data. By keeping streams open for requests that utilised the Servlet API's blocking I/O, clients were able to cause server-side threads to block eventually leading to thread exhaustion and a DoS.

Mitigation

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

Related links:

• http://web.nvd.nist.gov/view/vuln/detail?vulnId=CVE-2019-0199

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

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

• https://www.mail-archive.com/[email protected]/msg05156.html