CVE-2026-78437: Apache Software Foundation Apache Tomcat

High severity, CVSS 7.3. EPSS: 0.3% chance of exploitation in the next 30 days.

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.

Affected products

• Apache Software Foundation Apache Tomcat: from 11.0.19, up to and including 11.0.25; from 10.1.53, up to and including 10.1.59; from 9.0.116, up to and including 9.0.121

Published 2026-09-23. Last modified 2026-09-23.