---
id: CVE-2026-86247
title: >-
  Race condition within a thread vulnerability in Apache Tomcat Native allowed
  client certificate verification requirements to be down-graded for some
  configurations.




  This issue affects Apache Tomcat Native: from 2.0.0 through 2.0.15, f…
summary: >-
  Race condition within a thread vulnerability in Apache Tomcat Native allowed
  client certificate verification requirements to be down-graded for some
  configurations.




  This issue affects Apache Tomcat Native: from 2.0.0 through 2.0.15, f…
severity: high
cvss: 7.4
cvssVector: 'CVSS:3.1/AV:N/AC:H/PR:N/UI:N/S:U/C:H/I:H/A:N'
cwe:
  - CWE-366
vendor: Apache Software Foundation
product: Apache Tomcat Native
affected:
  - apache_tomcat_native >= 2.0.0 <= 2.0.15
  - apache_tomcat_native >= 1.3.0 <= 1.3.8
published: '2026-09-23'
updated: '2026-09-23'
sourceUpdated: '2026-09-23T19:19:41.923'
source: NVD
sourceUrl: 'https://nvd.nist.gov/vuln/detail/CVE-2026-86247'
references:
  - url: 'https://lists.apache.org/thread/obsson6zhvfg0wsp2bx602l61ltj87r1'
    label: security@apache.org
  - url: 'http://www.openwall.com/lists/oss-security/2026/09/23/33'
    label: af854a3a-2127-422b-91ae-364da2661108
tags:
  - nvd
  - cve.org
ssvc:
  exploitation: none
  automatable: 'no'
  technicalImpact: total
  timestamp: '2026-09-23T15:30:32.467469Z'
ingestedAt: '2026-09-23T13:24:43.399Z'
---

## Overview

Race condition within a thread vulnerability in Apache Tomcat Native allowed client certificate verification requirements to be down-graded for some configurations.



This issue affects Apache Tomcat Native: from 2.0.0 through 2.0.15, from 1.3.0 through 1.3.8. Unsupported versions may also be affected.



Users are recommended to upgrade to version 2.0.16 or 1.3.9, which fixes the issue.

## Remediation

Refer to the linked advisories for vendor-supplied fixes and affected version ranges.