CVE-2026-32990Network attack vector

Client certificate bypass via case-sensitive SNI validation

Published Apr 9, 2026 · Updated Apr 9, 2026

Improper SNI validation in Apache Tomcat affected releases allows remote attackers to bypass client certificate authentication. The strict SNI check compares the TLS SNI name and HTTP Host name case-sensitively, so differently cased forms evade the intended equality validation. Exploitation requires multiple virtual hosts, connector-level client certificate enforcement on one host, and another host whose TLS configuration does not require a client certificate.

CVSS severity5.3
Medium
EPSS probability0.31%
Next 30 days · Sep 16, 2026
Known exploitationUnconfirmed
Based on sourced intelligence
Hinoki checkNot available
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Summary

What happened

Improper SNI validation in Apache Tomcat affected releases allows remote attackers to bypass client certificate authentication. The strict SNI check compares the TLS SNI name and HTTP Host name case-sensitively, so differently cased forms evade the intended equality validation. Exploitation requires multiple virtual hosts, connector-level client certificate enforcement on one host, and another host whose TLS configuration does not require a client certificate.

The record

CVE
CVE-2026-32990
Published
Apr 9, 2026
Updated
Apr 9, 2026
Vendor
The Apache Software Foundation
Product
Apache Tomcat
Classifications
CWE-20, T1190
Attack vector
network
Privileges
unauthenticated

Timeline

How it unfolded

  1. Apr 9, 2026CVE publishedPublication date reported by the CVE source.
  2. Apr 9, 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=10.1.50 <=10.1.52
  2. Affected versionversion=11.0.15 <=11.0.19
  3. Affected versionversion=9.0.113 <=9.0.115

What conditions does exploitation require?

Attack vectornetwork
Required privilegesunauthenticated

What is affected?

The Apache Software Foundation · Apache Tomcatversion=10.1.50 <=10.1.52; version=11.0.15 <=11.0.19; version=9.0.113 <=9.0.115

Published CVSS scores

6.9GitHubCVSS:4.0/AV:N/AC:L/AT:N/PR:N/UI:N/VC:L/VI:N/VA:N/SC:N/SI:N/SA:N
5.3CISA-ADPCVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:L/I:N/A:N

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.

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

No observations available

Sep 10, 2026Sep 16, 2026
Latest reporting daySep 16, 2026
Latest daily unique IPsUnavailable
Prior 30-day averageUnavailable
SourceShadowserver honeypots (KEV)
Vectornetwork
Privilegesunauthenticated
Known exploitationUnconfirmed
Public exploitUnconfirmed

Weakness, pattern, technique

CWE-20Improper Input Validation
T1190Exploit Public-Facing Application

Public exploit references

No public exploit references are available in this record.

Labels summarize the accepted research assessment. They do not indicate a test against your environment.

Technologies

Your stack

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Your stack

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