Apache Tomcat: DoS via WebSocket chat example (CVE-2026-66299)
Uncontrolled Resource Consumption vulnerability in Apache Tomcat's WebSocket chat example. This issue affects Apache Tomcat: from 11.0.0 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 an uncontrolled resource consumption vulnerability (CWE-400) in the WebSocket chat example application bundled with Apache Tomcat. It affects Apache Tomcat versions from 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 allows an attacker to cause denial of service by exhausting server resources. The vulnerability does not affect users who have removed the example web application following security guidance. Fixed versions are 11.0.25, 10.1.58, and 9.0.121 (pending release). The CVSS v3.1 score is 7.5 (AV:N/AC:L/PR:N/UI:N/S:U/C:N/I:N/A:H), indicating a high impact on availability without confidentiality or integrity impact.
Potential Impact
Successful exploitation results in denial of service due to uncontrolled resource consumption in the WebSocket chat example application. There is no impact on confidentiality or integrity. Systems running affected versions with the example application enabled are vulnerable to resource exhaustion attacks.
Mitigation Recommendations
Users are recommended to remove the examples web application to mitigate the vulnerability. Alternatively, upgrading to Apache Tomcat versions 11.0.25, 10.1.58, or 9.0.121 (when released) will fix the issue. No other mitigation is indicated by the vendor advisory.
Apache Tomcat: DoS via WebSocket chat example (CVE-2026-66299)
Description
Uncontrolled Resource Consumption vulnerability in Apache Tomcat's WebSocket chat example. This issue affects Apache Tomcat: from 11.0.0 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.
Affected software
pkg:bitnami/tomcatRun on your own infrastructure? Check whether these packages are installed with threat-finder — our free open-source scanner.
AI-Powered Analysis
Machine-generated threat intelligence
Technical Analysis
CVE-2026-66299 is an uncontrolled resource consumption vulnerability (CWE-400) in the WebSocket chat example application bundled with Apache Tomcat. It affects Apache Tomcat versions from 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 allows an attacker to cause denial of service by exhausting server resources. The vulnerability does not affect users who have removed the example web application following security guidance. Fixed versions are 11.0.25, 10.1.58, and 9.0.121 (pending release). The CVSS v3.1 score is 7.5 (AV:N/AC:L/PR:N/UI:N/S:U/C:N/I:N/A:H), indicating a high impact on availability without confidentiality or integrity impact.
Potential Impact
Successful exploitation results in denial of service due to uncontrolled resource consumption in the WebSocket chat example application. There is no impact on confidentiality or integrity. Systems running affected versions with the example application enabled are vulnerable to resource exhaustion attacks.
Mitigation Recommendations
Users are recommended to remove the examples web application to mitigate the vulnerability. Alternatively, upgrading to Apache Tomcat versions 11.0.25, 10.1.58, or 9.0.121 (when released) will fix the issue. No other mitigation is indicated by the vendor advisory.
Technical Details
- Gcve Source
- db.gcve.eu
- Osv Id
- GHSA-rpf9-hrjr-88fv
- Osv Schema Version
- 1.4.0
- Aliases
- ["CVE-2026-66299"]
- Database Specific Severity
- HIGH
- Cvss Version
- 3.1
- State
- PUBLISHED
Threat ID: 6a6941de9c2644c7f86c54d8
Added to database: 07/28/2026, 23:57:18 UTC
Last enriched: 08/07/2026, 03:36:36 UTC
Last updated: 09/12/2026, 10:01:32 UTC
Views: 382
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