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CVE-2026-86248: CLIENT_CERT authentication does not fail as expected for some scenarios when soft fail is disabled in Apache Software Foundation Apache Tomcat

0
Critical
VulnerabilityCVE-2026-86248cvecve-2026-86248
Published: 09/23/2026 (09/23/2026, 11:29:35 UTC)
Source: CVE Database V5
Vendor/Project: Apache Software Foundation
Product: Apache Tomcat

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.

CVSS v3.1

Score 9.8critical

Attack Vector
Network
Attack Complexity
Low
Privileges Required
None
User Interaction
None
Scope
Unchanged
Confidentiality
High
Integrity
High
Availability
High
CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:H/I:H/A:H

Affected software

Apache Software Foundation

Apache Tomcat

Affected versions
>=11.0.0-M14 <=11.0.25>=10.1.22 <=10.1.59>=9.0.92 <=9.0.121
Mavenmore threats →ai
org.apache.tomcat/tomcat
pkg:maven/org.apache.tomcat/tomcat
Affected versions
>=11.0.0-M14 <=11.0.25>=10.1.22 <=10.1.59>=9.0.92 <=9.0.121

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AI-Powered Analysis

Machine-generated threat intelligence

AILast updated: 09/23/2026, 11:48:35 UTC

Technical Analysis

CVE-2026-86248 describes a flaw in Apache Tomcat's CLIENT_CERT authentication mechanism where, under specific conditions with soft fail disabled, authentication does not fail as expected. This could potentially allow bypassing expected authentication failure behavior. The vulnerability affects Apache Tomcat versions 11.0.0-M14 through 11.0.25, 10.1.22 through 10.1.59, and 9.0.92 through 9.0.121. The issue is resolved in versions 11.0.26, 10.1.60, and 9.0.122.

Potential Impact

The vulnerability may cause CLIENT_CERT authentication to succeed or not fail as intended in some scenarios when soft fail is disabled, potentially undermining authentication controls. No information about active exploitation or specific attack vectors is provided.

Mitigation Recommendations

Users should upgrade Apache Tomcat to versions 11.0.26, 10.1.60, or 9.0.122 or later, where this issue is fixed. No alternative mitigations are specified.

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Technical Details

Data Version
5.2
Assigner Short Name
apache
Date Reserved
2026-09-06T10:25:16.193Z
State
PUBLISHED

Threat ID: 6ab3b90df7a7c54106b30f17

Added to database: 09/23/2026, 11:33:33 UTC

Last enriched: 09/23/2026, 11:48:35 UTC

Last updated: 09/24/2026, 01:58:43 UTC

Views: 10

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