Apache Tomcat: DoS via WebSocket chat example

MITRE NVD CVE.ORG JSON API

Summary

CVECVE-2026-66299
StatePUBLISHED
Assignerapache
Source PriorityCVE Program / NVD first with legacy fallback
Published2026-07-28 15:17:50 UTC
Updated2026-07-28 18:17:23 UTC
DescriptionUncontrolled 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.

Risk And Classification

Primary CVSS: v3.1 7.5 HIGH from ADP

CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:N/I:N/A:H

EPSS: 0.003100000 probability, percentile 0.233860000 (date 2026-07-29)

Problem Types: CWE-400 | CWE-400 CWE-400 Uncontrolled Resource Consumption

VersionSourceTypeScoreSeverityVector
3.1ADPDECLARED7.5HIGHCVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:N/I:N/A:H
3.1134c704f-9b21-4f2e-91b3-4a467353bcc0Secondary7.5HIGHCVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:N/I:N/A:H

CVSS v3.1 Breakdown

Attack Vector
Network
Attack Complexity
Low
Privileges Required
None
User Interaction
None
Scope
Unchanged
Confidentiality
None
Integrity
None
Availability
High

CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:N/I:N/A:H

Vendor Declared Affected Products

SourceVendorProductVersionPlatforms
CNA Apache Software Foundation Apache Tomcat affected 11.0.0-M20 11.0.24 semver Not specified
CNA Apache Software Foundation Apache Tomcat affected 10.1.24 10.1.57 semver Not specified
CNA Apache Software Foundation Apache Tomcat affected 9.0.89 9.0.120 semver Not specified
CNA Apache Software Foundation Apache Tomcat unaffected 8.5.100 semver Not specified

References

ReferenceSourceLinkTags
lists.apache.org/thread/8owczcc1o8qw1rxmg9gvfk4w2jnh4l5k [email protected] lists.apache.org
www.openwall.com/lists/oss-security/2026/07/28/25 af854a3a-2127-422b-91ae-364da2661108 www.openwall.com
CVE Program record CVE.ORG www.cve.org canonical
NVD vulnerability detail NVD nvd.nist.gov canonical, analysis

Vendor Comments And Credit

Discovery Credit

CNA: 4ra1n, pyn3rd and unam4 (en)

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