CVE-2019-0199: Apache Tomcat

High severity, CVSS 7.5. EPSS: 72.9% chance of exploitation in the next 30 days.

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.

Affected products

• Apache Tomcat: from 8.5.0, up to and including 8.5.37; from 9.0.1, up to and including 9.0.14; version 9.0.0 only

Published 2019-04-10. Last modified 2026-06-17.