CVE-2026-66299
Description
A flaw was found in Apache Tomcat. This uncontrolled resource consumption vulnerability, located in the WebSocket chat example, allows a remote attacker to cause a Denial of Service (DoS) by exhausting system resources. This can lead to the affected system becoming unresponsive or crashing.
Statement
This Moderate severity flaw in Apache Tomcat's WebSocket chat example could lead to a denial of service. The impact is limited as the vulnerable component is part of an example application, which is generally not deployed in production environments. Exploitation requires the example application to be present and accessible.
Mitigation
To mitigate this vulnerability, remove the `examples` web application from your Apache Tomcat installation. This can typically be achieved by deleting the `examples` directory or `examples.war` file from the `webapps` directory of your Tomcat installation. A restart of the Tomcat service may be required for the changes to take full effect.
Common Vulnerability Scoring System (CVSS) Score Details
Info alert:Important note
CVSS scores for open source components depend on vendor-specific factors (e.g. version or build chain). Therefore, Red Hat's score and impact rating can be different from NVD and other vendors. Red Hat remains the authoritative CVE Naming Authority (CNA) source for its products and services (see Red Hat classifications).
The following CVSS metrics and score provided are preliminary and subject to review.
CVSS v3 Score Breakdown
| Red Hat | NVD | cve.org | |
|---|---|---|---|
| Base Score | 5.3 | N/A | 7.5 |
| Attack Vector | Network | N/A | Network |
| Attack Complexity | Low | N/A | Low |
| Privileges Required | None | N/A | None |
| User Interaction | None | N/A | None |
| Scope | Unchanged | N/A | Unchanged |
| Confidentiality | None | N/A | None |
| Integrity Impact | None | N/A | None |
| Availability Impact | Low | N/A | High |
Vector
Red Hat: CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:N/I:N/A:L
cve.org: CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:N/I:N/A:H
Understanding the Weakness (CWE)
Availability
Technical Impact: DoS: Resource Consumption (CPU); DoS: Resource Consumption (Memory); DoS: Resource Consumption (Other)
When allocating resources without limits, an attacker could prevent other systems, applications, or processes from accessing the same type of resource. It can be easy for an attacker to consume many resources by rapidly making many requests or causing larger resources to be used than is needed.
Frequently Asked Questions
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