What is CVE-2026-66299?

CVE-2026-66299 is a high-severity vulnerability in Apache Software Foundation Tomcat, classified under Uncontrolled Resource Consumption. CVSS score: 7.5/10. Published 2026-07-28.

How severe is CVE-2026-66299?

High severity. CVSS v3 base score is 7.5 out of 10.

Resource exhaustion in Apache Software Foundation Tomcat

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 follow…

Vulnerability class: DoS (Denial of Service)

CVSS v3 metric

CVSS v3 base score 7.5 (High). Vector: CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:N/I:N/A:H.

Affected products

Apache Software Foundation Tomcat — versions 11.0.0-M20, 10.1.24, 9.0.89

Weakness classification (CWE)

CWE-400 — Uncontrolled Resource Consumption

References

security@apache.org (vendor-advisory)
af854a3a-2127-422b-91ae-364da2661108

Frequently asked questions

What is CVE-2026-66299?: CVE-2026-66299 is a high-severity vulnerability in Apache Software Foundation Tomcat, classified under Uncontrolled Resource Consumption. CVSS score: 7.5/10. Published 2026-07-28.
How severe is CVE-2026-66299?: High severity. CVSS v3 base score is 7.5 out of 10.