CVE-2026-66299 - Vulnerability Details - OpenCVE

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 CVSS v4.0

Attack Vector Network

Attack Complexity Low

Privileges Required None

Scope Unchanged

Confidentiality Impact None

Integrity Impact None

Availability Impact High

User Interaction None

No CVSS v3.0

No CVSS v2

This CVE is not in the KEV list.

Exploitation none

Automatable yes

Technical Impact partial

Vendors	Products
Apache	Tomcat

No data.

No data.

References

Link	Providers
https://lists.apache.org/thread/8owczcc1o8qw1rxmg9gvfk4w2jnh4l5k

History

Tue, 28 Jul 2026 20:00:00 +0000

Type	Values Removed	Values Added
First Time appeared		Apache Apache tomcat
Vendors & Products		Apache Apache tomcat

Tue, 28 Jul 2026 18:30:00 +0000

Type	Values Removed	Values Added
Metrics		cvssV3_1 `{'score': 7.5, 'vector': 'CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:N/I:N/A:H'}` ssvc `{'options': {'Automatable': 'yes', 'Exploitation': 'none', 'Technical Impact': 'partial'}, 'version': '2.0.3'}`

Tue, 28 Jul 2026 16:15:00 +0000

Type	Values Removed	Values Added
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.
Title		Apache Tomcat: DoS via WebSocket chat example
Weaknesses		CWE-400
References		https://lists.apache.org/thread/8owczcc1o8qw1rxmg9gvfk4w2jnh4l5k

MITRE

Status: PUBLISHED

Assigner: apache

Published: 2026-07-28T14:29:05.810Z

Updated: 2026-07-28T17:40:03.853Z

Reserved: 2026-07-24T14:53:11.561Z

Link: CVE-2026-66299

Vulnrichment

Updated: 2026-07-28T17:31:30.996Z

NVD

No data.

Redhat

No data.

{"dataType": "CVE_RECORD", "dataVersion": "5.2", "cveMetadata": {"cveId": "CVE-2026-66299", "assignerOrgId": "f0158376-9dc2-43b6-827c-5f631a4d8d09", "state": "PUBLISHED", "assignerShortName": "apache", "dateReserved": "2026-07-24T14:53:11.561Z", "datePublished": "2026-07-28T14:29:05.810Z", "dateUpdated": "2026-07-28T17:40:03.853Z"}, "containers": {"cna": {"affected": [{"defaultStatus": "unaffected", "product": "Apache Tomcat", "vendor": "Apache Software Foundation", "versions": [{"lessThanOrEqual": "11.0.24", "status": "affected", "version": "11.0.0-M20", "versionType": "semver"}, {"lessThanOrEqual": "10.1.57", "status": "affected", "version": "10.1.24", "versionType": "semver"}, {"lessThanOrEqual": "9.0.120", "status": "affected", "version": "9.0.89", "versionType": "semver"}, {"lessThanOrEqual": "8.5.100", "status": "unaffected", "version": "0", "versionType": "semver"}]}], "credits": [{"lang": "en", "type": "finder", "value": "4ra1n, pyn3rd and unam4"}], "descriptions": [{"lang": "en", "supportingMedia": [{"base64": false, "type": "text/html", "value": "<p>Uncontrolled Resource Consumption vulnerability in Apache Tomcat's WebSocket chat example.</p><p>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.</p><p>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.</p>"}], "value": "Uncontrolled Resource Consumption vulnerability in Apache Tomcat's WebSocket chat example.\n\nThis 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.\n\nUsers 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."}], "metrics": [{"other": {"content": {"text": "low"}, "type": "Textual description of severity"}}], "problemTypes": [{"descriptions": [{"cweId": "CWE-400", "description": "CWE-400 Uncontrolled Resource Consumption", "lang": "en", "type": "CWE"}]}], "providerMetadata": {"orgId": "f0158376-9dc2-43b6-827c-5f631a4d8d09", "shortName": "apache", "dateUpdated": "2026-07-28T14:29:05.810Z"}, "references": [{"tags": ["vendor-advisory"], "url": "https://lists.apache.org/thread/8owczcc1o8qw1rxmg9gvfk4w2jnh4l5k"}], "source": {"discovery": "EXTERNAL"}, "title": "Apache Tomcat: DoS via WebSocket chat example", "x_generator": {"engine": "Vulnogram 0.2.0"}}, "adp": [{"title": "CVE Program Container", "references": [{"url": "http://www.openwall.com/lists/oss-security/2026/07/28/25"}], "providerMetadata": {"orgId": "af854a3a-2127-422b-91ae-364da2661108", "shortName": "CVE", "dateUpdated": "2026-07-28T17:31:30.996Z"}}, {"metrics": [{"cvssV3_1": {"scope": "UNCHANGED", "version": "3.1", "baseScore": 7.5, "attackVector": "NETWORK", "baseSeverity": "HIGH", "vectorString": "CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:N/I:N/A:H", "integrityImpact": "NONE", "userInteraction": "NONE", "attackComplexity": "LOW", "availabilityImpact": "HIGH", "privilegesRequired": "NONE", "confidentialityImpact": "NONE"}}, {"other": {"type": "ssvc", "content": {"timestamp": "2026-07-28T17:39:48.240123Z", "id": "CVE-2026-66299", "options": [{"Exploitation": "none"}, {"Automatable": "yes"}, {"Technical Impact": "partial"}], "role": "CISA Coordinator", "version": "2.0.3"}}}], "title": "CISA ADP Vulnrichment", "providerMetadata": {"orgId": "134c704f-9b21-4f2e-91b3-4a467353bcc0", "shortName": "CISA-ADP", "dateUpdated": "2026-07-28T17:40:03.853Z"}}]}}

{"dataType": "CVE_RECORD", "containers": {"adp": [{"title": "CVE Program Container", "references": [{"url": "http://www.openwall.com/lists/oss-security/2026/07/28/25"}], "providerMetadata": {"orgId": "af854a3a-2127-422b-91ae-364da2661108", "shortName": "CVE", "dateUpdated": "2026-07-28T17:31:30.996Z"}}, {"title": "CISA ADP Vulnrichment", "metrics": [{"cvssV3_1": {"scope": "UNCHANGED", "version": "3.1", "baseScore": 7.5, "attackVector": "NETWORK", "baseSeverity": "HIGH", "vectorString": "CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:N/I:N/A:H", "integrityImpact": "NONE", "userInteraction": "NONE", "attackComplexity": "LOW", "availabilityImpact": "HIGH", "privilegesRequired": "NONE", "confidentialityImpact": "NONE"}}, {"other": {"type": "ssvc", "content": {"id": "CVE-2026-66299", "role": "CISA Coordinator", "options": [{"Exploitation": "none"}, {"Automatable": "yes"}, {"Technical Impact": "partial"}], "version": "2.0.3", "timestamp": "2026-07-28T17:39:48.240123Z"}}}], "providerMetadata": {"orgId": "134c704f-9b21-4f2e-91b3-4a467353bcc0", "shortName": "CISA-ADP", "dateUpdated": "2026-07-28T17:39:12.191Z"}}], "cna": {"title": "Apache Tomcat: DoS via WebSocket chat example", "source": {"discovery": "EXTERNAL"}, "credits": [{"lang": "en", "type": "finder", "value": "4ra1n, pyn3rd and unam4"}], "metrics": [{"other": {"type": "Textual description of severity", "content": {"text": "low"}}}], "affected": [{"vendor": "Apache Software Foundation", "product": "Apache Tomcat", "versions": [{"status": "affected", "version": "11.0.0-M20", "versionType": "semver", "lessThanOrEqual": "11.0.24"}, {"status": "affected", "version": "10.1.24", "versionType": "semver", "lessThanOrEqual": "10.1.57"}, {"status": "affected", "version": "9.0.89", "versionType": "semver", "lessThanOrEqual": "9.0.120"}, {"status": "unaffected", "version": "0", "versionType": "semver", "lessThanOrEqual": "8.5.100"}], "defaultStatus": "unaffected"}], "references": [{"url": "https://lists.apache.org/thread/8owczcc1o8qw1rxmg9gvfk4w2jnh4l5k", "tags": ["vendor-advisory"]}], "x_generator": {"engine": "Vulnogram 0.2.0"}, "descriptions": [{"lang": "en", "value": "Uncontrolled Resource Consumption vulnerability in Apache Tomcat's WebSocket chat example.\n\nThis 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.\n\nUsers 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.", "supportingMedia": [{"type": "text/html", "value": "<p>Uncontrolled Resource Consumption vulnerability in Apache Tomcat's WebSocket chat example.</p><p>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.</p><p>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.</p>", "base64": false}]}], "problemTypes": [{"descriptions": [{"lang": "en", "type": "CWE", "cweId": "CWE-400", "description": "CWE-400 Uncontrolled Resource Consumption"}]}], "providerMetadata": {"orgId": "f0158376-9dc2-43b6-827c-5f631a4d8d09", "shortName": "apache", "dateUpdated": "2026-07-28T14:29:05.810Z"}}}, "cveMetadata": {"cveId": "CVE-2026-66299", "state": "PUBLISHED", "dateUpdated": "2026-07-28T17:40:03.853Z", "dateReserved": "2026-07-24T14:53:11.561Z", "assignerOrgId": "f0158376-9dc2-43b6-827c-5f631a4d8d09", "datePublished": "2026-07-28T14:29:05.810Z", "assignerShortName": "apache"}, "dataVersion": "5.2"}