Incomplete Cleanup CVE-2026-78437 in Apache Tomcat 9/10/11 before 9.0.122
CVE-2026-78437 Published on September 23, 2026
Apache Tomcat: HTTP/2 DoS via malformed request
Incomplete cleanup vulnerability in Apache Tomcat allows a malformed request to potentially (depends on timing) cause one request from another user to fail.
This issue affects Apache Tomcat: from 11.0.19 through 11.0.25, from 10.1.53 through 10.1.59, from 9.0.116 through 9.0.121.
Users are recommended to upgrade to version 11.0.26, 10.1.60 or 9.0.122, which fix the issue.
Vulnerability Analysis
CVE-2026-78437 can be exploited with network access, and does not require authorization privileges or user interaction. This vulnerability is considered to have a low attack complexity. The potential impact of an exploit of this vulnerability is considered to be low. considered to have a small impact on confidentiality and integrity and availability.
Weakness Type
What is an Insufficient Cleanup Vulnerability?
The software does not properly "clean up" and remove temporary or supporting resources after they have been used.
CVE-2026-78437 has been classified to as an Insufficient Cleanup vulnerability or weakness.
Products Associated with CVE-2026-78437
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Affected Versions
Apache Software Foundation Apache Tomcat:- Version 11.0.19, <= 11.0.25 is affected.
- Version 10.1.53, <= 10.1.59 is affected.
- Version 9.0.116, <= 9.0.121 is affected.
- Before and including 8.5.100 is unaffected.