CVE-2026-66299

Uncontrolled Resource Consumption vulnerability in Apache Tomcat's WebSocket chat example. This issue affects Apache Tomcat: from 11.0.0-M20 through 11.0.24, from 10.1.24 through 10.1.57, from 9.0.89 through 9.0.120. Users who have followed the security guidance to remove the examples web application are not affected by this issue. Users are recommended to remove the examples web application or to upgrade to version 11.0.25, 10.1.58 or 9.0.121 (when released), which fix the issue.

Score

CVSS 3.1 7.5 High

Status

Analyzed - security@apache.org

Published

2026-07-28

Last modified

2026-10-24

Weaknesses

CWE-400

Affected products

• Tomcat (Apache)
• Apache Tomcat (Apache Software Foundation)

References

• https://lists.apache.org/thread/8owczcc1o8qw1rxmg9gvfk4w2jnh4l5k
• http://www.openwall.com/lists/oss-security/2026/07/28/25