Description

In Apache Tomcat 9.0.0.M1 to 9.0.0.M18 and 8.5.0 to 8.5.12, the handling of an HTTP/2 GOAWAY frame for a connection did not close streams associated with that connection that were currently waiting for a WINDOW_UPDATE before allowing the application to write more data. These waiting streams each consumed a thread. A malicious client could therefore construct a series of HTTP/2 requests that would consume all available processing threads.

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-2017-5650

• http://seclists.org/oss-sec/2017/q2/56

• http://tomcat.apache.org/security-8.html#Fixed_in_Apache_Tomcat_8.5.13