CVE-2026-66299: CWE-400 Uncontrolled Resource Consumption in Apache Software Foundation Apache Tomcat
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.
AI Analysis
Technical Summary
CVE-2026-66299 is a CWE-400 uncontrolled resource consumption vulnerability in the WebSocket chat example application of Apache Tomcat. It affects multiple version branches: 11.0.0-M20 through 11.0.24, 10.1.24 through 10.1.57, and 9.0.89 through 9.0.120. The vulnerability can cause denial of service by exhausting resources. The vendor recommends removing the examples web application or upgrading to fixed versions 11.0.25, 10.1.58, or 9.0.121 (pending release).
Potential Impact
The vulnerability allows an attacker to cause uncontrolled resource consumption leading to denial of service (availability impact) on affected Apache Tomcat servers running the vulnerable WebSocket chat example. There is no confidentiality or integrity impact reported.
Mitigation Recommendations
Users should remove the examples web application if it is deployed, as this prevents exposure to the vulnerability. Alternatively, upgrading to Apache Tomcat versions 11.0.25, 10.1.58, or 9.0.121 (when released) will fix the issue. Patch status is not yet confirmed for 9.0.121 as it is pending release; check the vendor advisory for updates.
CVE-2026-66299: CWE-400 Uncontrolled Resource Consumption in Apache Software Foundation Apache Tomcat
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.
CVSS v3.1
Score 7.5high
Affected software
Apache Software Foundation
Apache Tomcat
Weaknesses
AI-Powered Analysis
Machine-generated threat intelligence
Technical Analysis
CVE-2026-66299 is a CWE-400 uncontrolled resource consumption vulnerability in the WebSocket chat example application of Apache Tomcat. It affects multiple version branches: 11.0.0-M20 through 11.0.24, 10.1.24 through 10.1.57, and 9.0.89 through 9.0.120. The vulnerability can cause denial of service by exhausting resources. The vendor recommends removing the examples web application or upgrading to fixed versions 11.0.25, 10.1.58, or 9.0.121 (pending release).
Potential Impact
The vulnerability allows an attacker to cause uncontrolled resource consumption leading to denial of service (availability impact) on affected Apache Tomcat servers running the vulnerable WebSocket chat example. There is no confidentiality or integrity impact reported.
Mitigation Recommendations
Users should remove the examples web application if it is deployed, as this prevents exposure to the vulnerability. Alternatively, upgrading to Apache Tomcat versions 11.0.25, 10.1.58, or 9.0.121 (when released) will fix the issue. Patch status is not yet confirmed for 9.0.121 as it is pending release; check the vendor advisory for updates.
Technical Details
- Data Version
- 5.2
- Assigner Short Name
- apache
- Date Reserved
- 2026-07-24T14:53:11.561Z
- State
- PUBLISHED
Threat ID: 6a68beba9c2644c7f8c13fbe
Added to database: 07/28/2026, 14:37:46 UTC
Last enriched: 07/29/2026, 17:09:58 UTC
Last updated: 09/10/2026, 20:01:20 UTC
Views: 241
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