CVE-2026-42498: Apache Tomcat - WebSocket authentication header exposure
(updated )
Versions Affected: Apache Tomcat 11.0.0-M1 to 11.0.21 Apache Tomcat 10.1.0-M1 to 10.1.54 Apache Tomcat 9.0.2 to 9.0.117 Older, unsupported versions may also be affected
Description: If a WebSocket request was redirected after authentication, Tomcat’s WebSocket client would present the most recent authentication header to the redirect target host.
Mitigation: Users of the affected versions should apply one of the following mitigations:
- Upgrade to Apache Tomcat 11.0.22 or later
- Upgrade to Apache Tomcat 10.1.55 or later
- Upgrade to Apache Tomcat 9.0.118 or later
Credit: This issue was identified by lokerxx
References
- github.com/advisories/GHSA-fv25-8xcx-gqjc
- github.com/apache/tomcat/commit/169d725788ea6aec217ecac70fe4161c837ba423
- github.com/apache/tomcat/commit/6cbe274592ef2d11607b5b188e1df649de52f8d5
- github.com/apache/tomcat/commit/b7b173694d588ddcfa432f079baf763cbbbaa5c4
- lists.apache.org/thread/n61zwf75jrv09rz90j4jssncm244bwdb
- nvd.nist.gov/vuln/detail/CVE-2026-42498
- tomcat.apache.org/security-10.html
- tomcat.apache.org/security-11.html
- tomcat.apache.org/security-9.html
Code Behaviors & Features
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