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
Affected software
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| Platform | Package | Vulnerable versions | Fixed in |
|---|---|---|---|
| Java / Kotlin (Maven) | org.apache.tomcat.embed:tomcat-embed-core | < 9.0.118, >= 10.1.0-M1, < 10.1.55, >= 11.0.0-M1, < 11.0.22 | 9.0.118, 10.1.55, 11.0.22 |
| Java / Kotlin (Maven) | org.apache.tomcat:tomcat | < 9.0.118, >= 10.1.0-M1, < 10.1.55, >= 11.0.0-M1, < 11.0.22 | 9.0.118, 10.1.55, 11.0.22 |
| Java / Kotlin (Maven) | org.apache.tomcat:tomcat-catalina | < 9.0.118, >= 10.1.0-M1, < 10.1.55, >= 11.0.0-M1, < 11.0.22 | 9.0.118, 10.1.55, 11.0.22 |
References
- https://nvd.nist.gov/vuln/detail/CVE-2026-42498
- https://github.com/apache/tomcat/commit/169d725788ea6aec217ecac70fe4161c837ba423
- https://github.com/apache/tomcat/commit/6cbe274592ef2d11607b5b188e1df649de52f8d5
- https://github.com/apache/tomcat/commit/b7b173694d588ddcfa432f079baf763cbbbaa5c4
- https://github.com/apache/tomcat
- https://lists.apache.org/thread/n61zwf75jrv09rz90j4jssncm244bwdb
- https://tomcat.apache.org/security-10.html
- https://tomcat.apache.org/security-11.html
- https://tomcat.apache.org/security-9.html
- http://www.openwall.com/lists/oss-security/2026/05/12/14
- CVSS vector
CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:L/I:L/A:L- Weakness (CWE)
CWE-200- Platform
- Java / Kotlin (Maven)
- Package
org.apache.tomcat.embed:tomcat-embed-core, org.apache.tomcat:tomcat, org.apache.tomcat:tomcat-catalina- Disclosed
- 12.05.2026
- Updated
- 11.10.2026 13:20
Sources and licenses
OSV / GitHub Advisory Database - GHSA-fv25-8xcx-gqjc - CC BY 4.0
Vulnerability history: org.apache.tomcat:tomcat
All published vulnerabilities of this package (Java / Kotlin (Maven)), newest first. Shows whether this is a one-off slip or a package that needs watching.
- Total entries
- 162
- First → latest
- 12.2018 08.2026
- Without a fix
- 20
- Exploited in attacks
- 1
Severity breakdown
- Critical 8
- High 40
- Medium 102
- Low 12
Disclosures per year
- 2018: 1
- 2019: 1
- 2020: 2
- 2021: 5
- 2022: 125
- 2023: 3
- 2024: 2
- 2025: 4
- 2026: 19
-
Apache Tomcat - WebSocket authentication header exposure this entry
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