CVE-2025-53506

CVE-2025-53506: Apache Tomcat: DoS via excessive h2 streams at connection start

Vendor Apache Software Foundation
Product Apache Tomcat
Weakness CWE-400
Published July 10, 2025
Last update November 4, 2025

CVSS base score

What the vulnerability does

Description

Uncontrolled Resource Consumption vulnerability in Apache Tomcat if an HTTP/2 client did not acknowledge the initial settings frame that reduces the maximum permitted concurrent streams. This issue affects Apache Tomcat: from 11.0.0-M1 through 11.0.8, from 10.1.0-M1 through 10.1.42, from 9.0.0.M1 through 9.0.106. The following versions were EOL at the time the CVE was created but are known to be affected: 8.5.0 through 8.5.100. Other EOL versions may also be affected. Users are recommended to upgrade to version 11.0.9, 10.1.43 or 9.0.107, which fix the issue.

Key dates

Disclosure timeline

July 10, 2025 CVE published
November 4, 2025 Record updated