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 Packages

Maven org.apache.tomcat.embed:tomcat-embed-core

Affected versions: 9.0.0 (fixed in 9.0.16)

Maven org.apache.tomcat.embed:tomcat-embed-core

Affected versions: 8.0.0 (fixed in 8.5.38)

Related CVEs

CVE-2019-0199

Key Information

GHSA ID

GHSA-qcxh-w3j9-58qr

Published

June 15, 2020 6:51 PM

Last Modified

December 8, 2023 10:47 PM

CVSS Score

7.5 /10

Primary Ecosystem

Maven

Primary Package

org.apache.tomcat.embed:tomcat-embed-core

GitHub Reviewed

✓ Yes

Dataset

Last updated: September 11, 2025 6:35 AM

Data from GitHub Advisory Database. This information is provided for research and educational purposes.