CVE-2026-66299CWE-400denial-of-service

CVE-2026-66299

Medium · published July 28, 2026

CVSS v3.1
5.3
EPSS
1%
Percentile
45.4
In the wild
Unconfirmed
What it is

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.

The record
Technical detail
CVSS v3.1
5.3 · MEDIUM
Vector
CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:N/I:N/A:L
CVSS v4.0
Not supplied
EPSS
0.00553 · 45.4th percentile
Weakness
CWE-400 · Uncontrolled Resource Consumption
Published
2026-07-28T19:17Z
Affected products (10)
ProductVersionsFixed in
apache/tomcat≥ 9.0.89, < 9.0.1219.0.121
apache/tomcat≥ 10.1.24, < 10.1.5810.1.58
apache/tomcat≥ 11.0.1, < 11.0.2511.0.25
apache/tomcatall versions—
apache/tomcatall versions—
apache/tomcatall versions—
apache/tomcatall versions—
apache/tomcatall versions—
apache/tomcatall versions—
apache/tomcatall versions—
References (2)
https://lists.apache.org/thread/8owczcc1o8qw1rxmg9gvfk4w2jnh4l5k · [email protected]http://www.openwall.com/lists/oss-security/2026/07/28/25 · af854a3a-2127-422b-91ae-364da2661108
EPSS history
Timeline
  • 28 JUL 14:29Z
    Apache Tomcat: DoS via WebSocket chat example
    cvelistv5