CVE-2026-42498 — Vulnerability in...

HIGH

Apache Tomcat - WebSocket authentication header exposure

Published May 12, 2026Updated September 10, 2026Source: osv

Summary

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

Advisory Timeline

First published May 12, 2026 (153 days ago).
Last revised September 10, 2026 — 120 days after initial publication.

Remediation

Upgrade to the fixed version using your package manager.

Maven

Update org.apache.tomcat.embed:tomcat-embed-core to 11.0.22 or later

<!-- Update pom.xml dependency version to 11.0.22 for org.apache.tomcat.embed:tomcat-embed-core -->

Maven

Update org.apache.tomcat.embed:tomcat-embed-core to 9.0.118 or later

<!-- Update pom.xml dependency version to 9.0.118 for org.apache.tomcat.embed:tomcat-embed-core -->

Maven

Update org.apache.tomcat.embed:tomcat-embed-core to 10.1.55 or later

<!-- Update pom.xml dependency version to 10.1.55 for org.apache.tomcat.embed:tomcat-embed-core -->

Maven

Update org.apache.tomcat:tomcat-catalina to 9.0.118 or later

<!-- Update pom.xml dependency version to 9.0.118 for org.apache.tomcat:tomcat-catalina -->

Maven

Update org.apache.tomcat:tomcat to 11.0.22 or later

<!-- Update pom.xml dependency version to 11.0.22 for org.apache.tomcat:tomcat -->

Maven

Update org.apache.tomcat:tomcat-catalina to 11.0.22 or later

<!-- Update pom.xml dependency version to 11.0.22 for org.apache.tomcat:tomcat-catalina -->

Maven

Update org.apache.tomcat:tomcat to 10.1.55 or later

<!-- Update pom.xml dependency version to 10.1.55 for org.apache.tomcat:tomcat -->

Maven

Update org.apache.tomcat:tomcat to 9.0.118 or later

<!-- Update pom.xml dependency version to 9.0.118 for org.apache.tomcat:tomcat -->

Maven

Update org.apache.tomcat:tomcat-catalina to 10.1.55 or later

<!-- Update pom.xml dependency version to 10.1.55 for org.apache.tomcat:tomcat-catalina -->

After upgrading, run your dependency scanner again to confirm the vulnerability is resolved.

Affected Packages (9)

Affects 1 ecosystem: maven (3).

Package	Ecosystem	Affected	Fixed In
org.apache.tomcat.embed:tomcat-embed-core	maven	11.0.0, 11.0.0-M1, 11.0.0-M10, 11.0.0-M11 (+38 more)	11.0.22
org.apache.tomcat.embed:tomcat-embed-core	maven	7.0.0, 7.0.100, 7.0.103, 7.0.104 (+318 more)	9.0.118
org.apache.tomcat.embed:tomcat-embed-core	maven	10.1.0, 10.1.0-M1, 10.1.0-M10, 10.1.0-M11 (+57 more)	10.1.55
org.apache.tomcat:tomcat-catalina	maven	7.0.0, 7.0.100, 7.0.103, 7.0.104 (+318 more)	9.0.118
org.apache.tomcat:tomcat	maven	11.0.0, 11.0.0-M1, 11.0.0-M10, 11.0.0-M11 (+38 more)	11.0.22
org.apache.tomcat:tomcat-catalina	maven	11.0.0, 11.0.0-M1, 11.0.0-M10, 11.0.0-M11 (+38 more)	11.0.22
org.apache.tomcat:tomcat	maven	10.1.0, 10.1.0-M1, 10.1.0-M10, 10.1.0-M11 (+57 more)	10.1.55
org.apache.tomcat:tomcat	maven	7.0.100, 7.0.103, 7.0.104, 7.0.105 (+294 more)	9.0.118
org.apache.tomcat:tomcat-catalina	maven	10.1.0, 10.1.0-M1, 10.1.0-M10, 10.1.0-M11 (+57 more)	10.1.55

Vulnerability Classification

Common Weakness Enumeration (CWE) identifiers for this vulnerability type.

CWE-200
Information ExposureMITRE

CVSS Score Breakdown

What the CVSS (Common Vulnerability Scoring System) 7.3 score means for each attack dimension.

Attack Vector

Network

Attack Complexity

Low

Privileges Required

None

User Interaction

None

Scope

Unchanged

Confidentiality

Low

Integrity

Low

Availability

Low

CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:L/I:L/A:L

References

Frequently Asked Questions

What is CVE-2026-42498?: Apache Tomcat - WebSocket authentication header exposure This vulnerability has been assigned a severity rating of HIGH (CVSS score: 7.3/10).
How do I check if my project is affected by CVE-2026-42498?: CVE-2026-42498 affects org.apache.tomcat.embed:tomcat-embed-core, org.apache.tomcat:tomcat-catalina and org.apache.tomcat:tomcat. Use GeekWala's free vulnerability scanner to check your dependencies against CVE-2026-42498 and 200,000+ other known vulnerabilities.

Severity & Exploitability

CVSS Score

7.3

High exploitability or significant impact. Prioritize remediation within days.

Also Known As

GHSA-fv25-8xcx-gqjc

BIT-tomcat-2026-42498

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