CVE-2026-41920Network attack vector

SNI policy bypass via partial hostname matching

Published Jul 29, 2026 · Updated Jul 29, 2026

Improper access control in Apache Traffic Server 9.0.0 through 9.1.14 and 10.0.0 through 10.1.3 allows remote attackers to bypass SNI policies. SSLSNIConfig compares only a hostname prefix without confirming equal full-string lengths, so a crafted Host value can pass as the TLS SNI name. The bypass requires an inbound TLS route with a relevant sni.yaml verify_client or ip_allow policy and can defeat client-certificate or source-IP restrictions.

CVSS severity7.0
High
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 access control in Apache Traffic Server 9.0.0 through 9.1.14 and 10.0.0 through 10.1.3 allows remote attackers to bypass SNI policies. SSLSNIConfig compares only a hostname prefix without confirming equal full-string lengths, so a crafted Host value can pass as the TLS SNI name. The bypass requires an inbound TLS route with a relevant sni.yaml verify_client or ip_allow policy and can defeat client-certificate or source-IP restrictions.

The record

CVE
CVE-2026-41920
Published
Jul 29, 2026
Updated
Jul 29, 2026
Vendor
The Apache Software Foundation
Product
Apache Traffic Server
Classifications
CWE-284, T1190
Attack vector
network
Privileges
unauthenticated

Timeline

How it unfolded

  1. Jul 29, 2026CVE publishedPublication date reported by the CVE source.
  2. Jul 29, 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=10.0.0 <=10.1.3
  2. Affected versionversion=9.0.0 <=9.1.14

What conditions does exploitation require?

Attack vectornetwork
Required privilegesunauthenticated

What is affected?

The Apache Software Foundation · Apache Traffic Serverversion=10.0.0 <=10.1.3; version=9.0.0 <=9.1.14

Published CVSS scores

7.0Apache Software FoundationCVSS:4.0/AV:N/AC:L/AT:P/PR:N/UI:N/VC:N/VI:N/VA:N/SC:H/SI:H/SA:N
9.3Apache Software FoundationCVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:C/C:L/I:H/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.

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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-284Improper Access Control
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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