CVE-2026-86248Network attack vectorHinoki check available

Client-certificate authentication bypass via OCSP fail-open

Published Sep 23, 2026 · Updated Sep 23, 2026

Authentication bypass in affected Apache Tomcat 9, 10, and 11 releases allows remote attackers to complete CLIENT_CERT authentication. OpenSSLEngine.processOCSP mishandles some unknown or failed OCSP results in the FFM path instead of preserving a verification error when ocspSoftFail is false. Affected ranges are 9.0.92 through 9.0.121, 10.1.22 through 10.1.59, and 11.0.0-M14 through 11.0.25; the bypass admits a certificate that policy requires Tomcat to reject.

CVSS severityUnavailable
Unscored
EPSS probability0.39%
Next 30 days · Oct 19, 2026
Known exploitationUnconfirmed
Based on sourced intelligence
Hinoki checkAvailable
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Summary

What happened

Authentication bypass in affected Apache Tomcat 9, 10, and 11 releases allows remote attackers to complete CLIENT_CERT authentication. OpenSSLEngine.processOCSP mishandles some unknown or failed OCSP results in the FFM path instead of preserving a verification error when ocspSoftFail is false. Affected ranges are 9.0.92 through 9.0.121, 10.1.22 through 10.1.59, and 11.0.0-M14 through 11.0.25; the bypass admits a certificate that policy requires Tomcat to reject.

The record

CVE
CVE-2026-86248
Published
Sep 23, 2026
Updated
Sep 23, 2026
Vendor
The Apache Software Foundation
Product
Apache Tomcat
Classifications
T1190
Attack vector
network
Privileges
unauthenticated

Timeline

How it unfolded

  1. Sep 23, 2026CVE publishedPublication date reported by the CVE source.
  2. Sep 23, 2026Record updatedLatest update available in the CVE record.

Exploitability

Present is not the same as exploitable

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Is a vulnerable build present?

Compare these published version ranges with your installed build and any vendor patches.

  1. Affected versionversion=10.1.22 <=10.1.59
  2. Affected versionversion=11.0.0-M14 <=11.0.25
  3. Affected versionversion=9.0.92 <=9.0.121

What conditions does exploitation require?

Attack vectornetwork
Required privilegesunauthenticated

What is affected?

The Apache Software Foundation · Apache Tomcatversion=10.1.22 <=10.1.59; version=11.0.0-M14 <=11.0.25; version=9.0.92 <=9.0.121

Published CVSS scores

No CVSS assessment is available in this record.

CVSS describes severity. EPSS estimates exploitation probability.

Attacks

What attackers are doing with it

Daily unique IPs observed by Shadowserver honeypots for known exploited vulnerabilities (KEVs). Missing observations do not establish an absence of attacks.

Activity data is delayed. The latest report is Sep 28, 2026.

Daily unique IPsNo honeypot observations are available for this CVE in the selected window.

No observations available

Sep 22, 2026Sep 28, 2026
Latest reporting daySep 28, 2026
Latest daily unique IPsUnavailable
Prior 30-day averageUnavailable
SourceShadowserver honeypots (KEV)
Vectornetwork
Privilegesunauthenticated
Known exploitationUnconfirmed
Public exploitUnconfirmed

Weakness, pattern, technique

T1190Exploit Public-Facing Application

Public exploit references

No public exploit references are available in this record.

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Technologies

Your stack

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Your stack

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