# CVE-2026-66299: tomcat9: Uncontrolled Resource Consumption vulnerability in Apache Tomcat's WebSocket chat example

CVE-2026-66299 is fixed in 5 products on 1 platform, first by DEBIAN-CVE-2026-66299, released July 31, 2026. It is not reported as exploited. Patch Radar priority: Routine.

- Web page: https://patchblox.com/security/cve/CVE-2026-66299
- Priority: Routine
- CVSS: 5.3 (medium)
- EPSS: 0.0055
- CISA KEV: not listed
- Exploited (vendor report): no
- Publicly disclosed: no
- Published: Jul 28, 2026

## 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.

## Where it's fixed

| Platform | Product | Fixed in | Fix | Released |
|---|---|---|---|---|
| Linux | jws6-tomcat RHEL 10 | 10.1.49-16.redhat_00016.1.el10jws | [RHSA-2026:73981](https://patchblox.com/security/data/fix/linux/rhsa-2026-73981.md) | Aug 25, 2026 |
| Linux | tomcat opensuse-leap 16.0 | 9.0.121-160000.1.1 | [OPENSUSE-SU-2026:21823-1](https://patchblox.com/security/data/fix/linux/opensuse-su-2026-21823-1.md) | Sep 9, 2026 |
| Linux | tomcat sles 15.6 | 9.0.121-150200.120.1 | [SUSE-SU-2026:4203-1](https://patchblox.com/security/data/fix/linux/suse-su-2026-4203-1.md) | Sep 16, 2026 |
| Linux | tomcat sles 15.7 | 9.0.121-150200.120.1 | [SUSE-SU-2026:4203-1](https://patchblox.com/security/data/fix/linux/suse-su-2026-4203-1.md) | Sep 16, 2026 |
| Linux | tomcat sles 16.0 | 9.0.121-160000.1.1 | [SUSE-SU-2026:23720-1](https://patchblox.com/security/data/fix/linux/suse-su-2026-23720-1.md) | Sep 9, 2026 |
| Linux | tomcat10 Debian 14 | 10.1.60-1 | [DEBIAN-CVE-2026-66299](https://patchblox.com/security/data/fix/linux/debian-cve-2026-66299.md) | Jul 31, 2026 |
| Linux | tomcat10 opensuse-leap 16.0 | 10.1.59-160000.1.1 | [OPENSUSE-SU-2026:21810-1](https://patchblox.com/security/data/fix/linux/opensuse-su-2026-21810-1.md) | Sep 8, 2026 |
| Linux | tomcat10 sles 15.6 | 10.1.59-150200.5.79.1 | [SUSE-SU-2026:4119-1](https://patchblox.com/security/data/fix/linux/suse-su-2026-4119-1.md) | Sep 10, 2026 |
| Linux | tomcat10 sles 15.7 | 10.1.59-150200.5.79.1 | [SUSE-SU-2026:4119-1](https://patchblox.com/security/data/fix/linux/suse-su-2026-4119-1.md) | Sep 10, 2026 |
| Linux | tomcat10 sles 16.0 | 10.1.59-160000.1.1 | [SUSE-SU-2026:23711-1](https://patchblox.com/security/data/fix/linux/suse-su-2026-23711-1.md) | Sep 8, 2026 |
| Linux | tomcat11 opensuse-leap 16.0 | 11.0.25-160000.1.1 | [OPENSUSE-SU-2026:21811-1](https://patchblox.com/security/data/fix/linux/opensuse-su-2026-21811-1.md) | Sep 8, 2026 |
| Linux | tomcat11 sles 15.6 | 11.0.25-150600.13.33.2 | [SUSE-SU-2026:4114-1](https://patchblox.com/security/data/fix/linux/suse-su-2026-4114-1.md) | Sep 9, 2026 |
| Linux | tomcat11 sles 15.7 | 11.0.25-150600.13.33.2 | [SUSE-SU-2026:4114-1](https://patchblox.com/security/data/fix/linux/suse-su-2026-4114-1.md) | Sep 9, 2026 |
| Linux | tomcat11 sles 16.0 | 11.0.25-160000.1.1 | [SUSE-SU-2026:23710-1](https://patchblox.com/security/data/fix/linux/suse-su-2026-23710-1.md) | Sep 8, 2026 |
| Linux | tomcat9 Debian 12.15 (bookworm) | 9.0.70-2 | [DEBIAN-CVE-2026-66299](https://patchblox.com/security/data/fix/linux/debian-cve-2026-66299.md) | Jul 31, 2026 |
| Linux | tomcat9 Debian 13.5 (trixie) | 9.0.70-2 | [DEBIAN-CVE-2026-66299](https://patchblox.com/security/data/fix/linux/debian-cve-2026-66299.md) | Jul 31, 2026 |
| Linux | tomcat9 Debian 14 | 9.0.70-2 | [DEBIAN-CVE-2026-66299](https://patchblox.com/security/data/fix/linux/debian-cve-2026-66299.md) | Jul 31, 2026 |

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Data as of 2026-11-08T13:06:02Z UTC. Source: Patchblox Patch Radar (https://patchblox.com/security/patch-radar). Patchblox finds out-of-date software on Windows, macOS and Linux and updates it through release rings: https://patchblox.com/demo

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