# CVE-2026-76183: Apache Tomcat authentication bypass in WebSocket endpoints

Source: https://junglewise.ai/threats/cve-2026-76183-authentication-bypass-by-alternate-name-vulnerability-in-apache  
Publisher: Junglewise Threat Intelligence, https://junglewise.ai/threats  
Published: 2026-09-23. Updated: 2026-09-26  
License: CC BY 4.0 with a link back

CVE-2026-76183 · Severity: critical · CVSS 9.8 · Published 2026-09-23

Apache Tomcat is a Java-based application server used to run web applications and services. A security constraint bypass vulnerability in WebSocket endpoints allows attackers to access protected resources without proper authentication, potentially exposing sensitive data or enabling unauthorized actions on affected systems.

Technologies: [Apache Tomcat](https://junglewise.ai/threats/technologies/tomcat). Vendors: [Apache](https://junglewise.ai/threats/vendors/apache).

## Quick answers

**Is CVE-2026-76183 exploited in the wild?** No. Junglewise Threat Intelligence has no report of CVE-2026-76183 being exploited in the wild.

**How severe is CVE-2026-76183?** Critical severity, with a CVSS score of 9.8, published 23 September 2026.

**Which products and versions are affected?** Apache Tomcat 7.0.43 through 7.0.109.

**Is there a fix for CVE-2026-76183?** A patch was published on 2026-09-23: Fixed in Tomcat 11.0.26, 10.1.60, and 9.0.122 Junglewise finds every place you run it, drafts the upgrade and applies it once you approve.

**How is CVE-2026-76183 attacked?** It is attacked over the network, in a web application.

**Am I affected by CVE-2026-76183?** Check whether you run Apache Tomcat at an affected version. Junglewise does that check for you around the clock: connect your code, cloud and domains, and it matches new vulnerabilities like this one against what you actually run and tells you when one reaches you.

## Technical details

An authentication bypass vulnerability in Apache Tomcat's WebSocket endpoint handling allows attackers to bypass security constraints through alternate name manipulation. The vulnerability affects multiple versions across major release lines and requires network access to WebSocket endpoints. A fix is available in versions 11.0.26, 10.1.60, and 9.0.122.

## Affected products

- Apache Tomcat 11.0.0-M1 through 11.0.25
- Apache Tomcat 10.1.0-M1 through 10.1.59
- Apache Tomcat 9.0.0-M1 through 9.0.121
- Apache Tomcat 8.5.0 through 8.5.100
- Apache Tomcat 7.0.43 through 7.0.109

## Timeline

- 2026-09-23: disclosed
- 2026-09-23: patched: Fixed in Tomcat 11.0.26, 10.1.60, and 9.0.122

## References

- [https://lists.apache.org/thread/45mxk8nj2q8pkhct6lfxkvtm2jpywrsp](https://lists.apache.org/thread/45mxk8nj2q8pkhct6lfxkvtm2jpywrsp)
- [http://www.openwall.com/lists/oss-security/2026/09/23/21](http://www.openwall.com/lists/oss-security/2026/09/23/21)

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