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CVE-2026-66299

Apache Tomcat: DoS via WebSocket chat example

Published: Jul 28, 2026Updated: Aug 5, 2026 Sources: CVE List NVDCWE-400
7.5HIGH
NVD MITRE
EPSS Score
0.5%
Top 63.0%
CISA KEV
Not in KEV
Exploits
No Known Exploits
Remediation
Patch Available
Self-Check
OpenVAS

Description

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.

No summary for this CVE yet.

CVSS Vector Breakdown

AV:NAC:LPR:NUI:NS:UC:NI:NA:H
Exploitability
AV:NAttack Vector
Network
AC:LAttack Complexity
Low
PR:NPrivileges Required
None
UI:NUser Interaction
None
Scope
S:UScope
Unchanged
Impact
C:NConfidentiality
None
I:NIntegrity
None
A:HAvailability
High
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Weaknesses

CWE-400

Affected Products

apache
oss-project·USaka apache httpd, apache http server
tomcatOn-premWeb App
Networking Infrastructure / load-balancer-proxy
Apache Software Foundation
oss-project·USaka apache foundation
Apache TomcatOn-premWeb App
Networking Infrastructure / load-balancer-proxy

Exploitability

Official Patch Available
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Attack Graph

Products CVE Techniques Tactics

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MITRE ATT&CK

1 technique
Impact
View detailed technique mapping

References

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

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