CVE-2026-86248
Received Received - Intake

CLIENT_CERT Authentication Bypass in Apache Tomcat

Publication date: 2026-09-23

Last updated on: 2026-09-23

Assigner: Apache Software Foundation

Description
CLIENT_CERT authentication does not fail as expected for some scenarios when soft fail is disabled vulnerability in Apache Tomcat. This issue affects Apache Tomcat: from 11.0.0-M14 through 11.0.25, from 10.1.22 through 10.1.59, from 9.0.92 through 9.0.121. Users are recommended to upgrade to version 11.0.26, 10.1.60 or 9.0.122, which fix the issue.

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Meta Information

Published
2026-09-23
Last Modified
2026-09-23
Generated
2026-09-23
AI Q&A
2026-09-23
EPSS Evaluated
N/A
NVD
CVE-2026-86248
EUVD
EUVD-2026-85234

Affected Vendors & Products

Showing 6 associated CPEs
Vendor Product Version / Range
apache tomcat From 11.0.0-M14 (inc) to 11.0.25 (inc)
apache tomcat From 10.1.22 (inc) to 10.1.59 (inc)
apache tomcat From 9.0.92 (inc) to 9.0.121 (inc)
apache tomcat 11.0.26
apache tomcat 10.1.60
apache tomcat 9.0.122

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Exploitability

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CWE ID Description
CWE-UNKNOWN

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Executive Summary

CLIENT_CERT authentication in Apache Tomcat fails to behave as expected when soft fail is disabled. This means the system may not properly reject invalid or unauthorized client certificates in certain scenarios, potentially allowing unintended access.

Detection Guidance

This vulnerability involves CLIENT_CERT authentication not failing properly when soft fail is disabled in Apache Tomcat. Detection requires checking Tomcat configuration files for improper soft fail settings and verifying if affected versions (11.0.0-M14 to 11.0.25, 10.1.22 to 10.1.59, 9.0.92 to 9.0.121) are running. Review server.xml and web.xml for clientAuth settings and test authentication flows.

Impact Analysis

This vulnerability could allow unauthorized users to bypass authentication checks if soft fail is disabled. This may lead to unauthorized access to sensitive data or services hosted on affected Tomcat servers.

Compliance Impact

This vulnerability does not directly affect compliance with GDPR or HIPAA as it relates to Apache Tomcat's CLIENT_CERT authentication behavior. Compliance impacts would depend on specific implementations and configurations rather than this technical flaw.

Mitigation Strategies

Upgrade Apache Tomcat to version 11.0.26, 10.1.60, or 9.0.122 or later to resolve the issue.

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