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7.5

Apache Tomcat can be made to run out of threads

CVE-2019-0199 · published 7 years ago
Summary

If a client uses the newer HTTP/2 protocol with Apache Tomcat versions 8.5.0 through 8.5.37 or 9.0.0.M1 through 9.0.14, it can open many channels and then stop communicating. Those idle channels hold Tomcat’s processing threads, eventually exhausting them and stopping the web site from responding. Upgrade Tomcat to the latest version or apply the vendor’s patch that limits how many channels a client can keep open.

What to do
  • Update apache org.apache.tomcat.embed:tomcat-embed-core to version 9.0.16.
  • Update apache org.apache.tomcat.embed:tomcat-embed-core to version 8.5.38.
  • Update apache org.apache.tomcat:tomcat-coyote to version 9.0.16.
  • Update apache org.apache.tomcat:tomcat-coyote to version 8.5.38.
  • Update debian tomcat9 to version 9.0.16-1.
Affected software
Ecosystem VendorProductAffected versions
maven apache org.apache.tomcat.embed:tomcat-embed-core >= 9.0.0, < 9.0.16
>= 8.0.0, < 8.5.38
Fix: upgrade to 9.0.16
– apache tomcat >= 8.5.0, <= 8.5.37
>= 9.0.1, <= 9.0.14
9.0.0
cpe:2.3:a:apache:tomcat:*:*:*:*:*:*:*:*
maven apache org.apache.tomcat:tomcat-coyote >= 9.0.0, < 9.0.16
>= 8.0.0, < 8.5.38
Fix: upgrade to 9.0.16
Debian:12 debian tomcat9 < 9.0.16-1
Fix: upgrade to 9.0.16-1
Original advisory text
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 ...
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.
References
Fix within
Internet-facing 14 days
Internal 60 days
  • Not known to be exploited
  • Can be exploited automatically (estimated)
  • Gives an attacker partial control (estimated)
Severity
7.5 High
Exploitation
73% chance of attack within 30 days
Type
CWE-400Uncontrolled Resource Consumption
Timeline
Published10 Apr 2019
Updated22 Sep 2026
First seen6 Mar 2026
Sources
GHSA-qcxh-w3j9-58qr · GHSA
CVE-2019-0199 · NVD
DEBIAN-CVE-2019-0199 · OSV
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