CVE-2026-78383: Apache Software Foundation Apache Tomcat

High severity, CVSS 7.5. EPSS: 0.4% chance of exploitation in the next 30 days.

Allocation of resources without limits or throttling vulnerability in Apache Tomcat allows an unauthenticated AJP request to pin an AJP processing thread leading to denial of service. This issue affects Apache Tomcat: from 11.0.0-M1 through 11.0.25, from 10.1.0-M1 through 10.1.59, from 9.0.0.M1 through 9.0.121. The following versions were EOL at the time the CVE was created but are known to be affected: from 8.5.0 through 8.5.100, from 7.0.0 through 7.0.109. Other unsupported versions may also be affected. 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 11.0.0-M1, up to and including 11.0.25; from 10.1.0-M1, up to and including 10.1.59; from 9.0.0.M1, up to and including 9.0.121; from 8.5.0, up to and including 8.5.100; from 7.0.0, up to and including 7.0.109

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