CVE-2026-78437 Apache Tomcat - HTTP/2 DoS via malformed request
Severity: Low
Vendor: The Apache Software Foundation
Versions Affected:
Apache Tomcat 11.0.19 to 11.0.25
Apache Tomcat 10.1.53 to 10.1.59
Apache Tomcat 9.0.116 to 9.0.121
Description:
A malformed HTTP/2 request could potentially (depends on timing) cause
one request from another user to fail.
Mitigation:
Users of the affected versions should apply one of the following
mitigations:
- Remove the examples web application
- Upgrade to Apache Tomcat 11.0.26
- Upgrade to Apache Tomcat 10.1.60
- Upgrade to Apache Tomcat 9.0.122
History:
2026-09-23 Original advisory
References:
[1] https://tomcat.apache.org/security-11.html
[2] https://tomcat.apache.org/security-10.html
[3] https://tomcat.apache.org/security-9.html
