CVE-2026-76183: Apache Tomcat: Bypass of security constraints for WebSocket endpoints
Authentication Bypass by Alternate Name vulnerability in Apache Tomcat allowed the security constraints for any WebSocket endpoint to be bypassed.
This issue affects Apache Tomcat: from 11.0.0-M1 through 11.0.25, from 10.1.0-M1 through 10.1.59, from 9.0.0.M1 through 9.0.121.
The following versions were EOS at the time the CVE was created but are known to be affected: from 8.5.0 through 8.5.100, from 7.0.43 through 7.0.109. Other unsupported versions may also be affected.
Users are recommended to upgrade to version 11.0.26, 10.1.60 or 9.0.122, which fix the issue.
Affected Software
Remediation
Recommended actions to resolve this vulnerability, in priority order.
- Upgrade
Upgrade
Apache Tomcatto a version that resolves this vulnerability.Fixed in 11.0.26 - Upgrade
Upgrade
Apache Tomcatto a version that resolves this vulnerability.Fixed in 10.1.60 - Upgrade
Upgrade
Apache Tomcatto a version that resolves this vulnerability.Fixed in 9.0.122
Event History
Frequently Asked Questions
Which deployments are exposed to this issue?
Deployments running affected Apache Tomcat versions with WebSocket endpoints protected by security constraints are exposed. The affected supported release lines are 11.0.0-M1 through 11.0.25, 10.1.0-M1 through 10.1.59, and 9.0.0.M1 through 9.0.121.
What does an attacker need to exploit the vulnerability?
The issue concerns bypassing security constraints for WebSocket endpoints through an alternate name. The available information does not specify whether prior authentication, a particular endpoint configuration, or other access is required.
Are end-of-support Tomcat releases affected?
Yes. Tomcat 8.5.0 through 8.5.100 and 7.0.43 through 7.0.109 were end of support when the CVE was created but are known to be affected; other unsupported versions may also be affected.
What versions remediate the issue?
Upgrade to Apache Tomcat 11.0.26, 10.1.60, or 9.0.122. These versions fix the security-constraint bypass.