Apache Tomcat - WebSocket authentication header exposure
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
describes (1)
Related CVEs.
| ID | severity | exploitable | ||
|---|---|---|---|---|
| CVE-2026-42498US | — | — | ||
Exposure of HTTP Authentication Header to unexpected hosts during WebSocket authentication vulnerability in Apache Tomcat.
This issue affects Apache Tomcat: from 11.0.0-M1 through… | ||||
references
External citations — patches, advisories, analysis.
- http://www.openwall.com/lists/oss-security/2026/05/12/14WEB
- https://github.com/apache/tomcatPACKAGE
- https://github.com/apache/tomcat/commit/169d725788ea6aec217ecac70fe4161c837ba423WEB
- https://github.com/apache/tomcat/commit/6cbe274592ef2d11607b5b188e1df649de52f8d5WEB
- https://github.com/apache/tomcat/commit/b7b173694d588ddcfa432f079baf763cbbbaa5c4WEB
- https://lists.apache.org/thread/n61zwf75jrv09rz90j4jssncm244bwdbWEB
- https://nvd.nist.gov/vuln/detail/CVE-2026-42498ADVISORY
- https://tomcat.apache.org/security-10.htmlWEB
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