CVE-2026-48491Public exploitNetwork attack vectorHinoki check available

Unauthenticated mTLS bypass via wildcard SNICheck lookup

Published Jun 23, 2026 · Updated Jun 23, 2026

Authentication bypass in Traefik Proxy 3.7.0 through 3.7.2 allows remote attackers to reach mTLS-protected backends via domain fronting. SNICheck resolves the HTTP Host header through exact TLSOptions map lookups, so a wildcard host falls back to permissive default options. Exploitation requires a wildcard router with stricter TLSOptions and another permissive SNI on the same entrypoint; the result is unauthorized backend access.

CVSS severity7.8
High
EPSS probability0.36%
Next 30 days · Sep 16, 2026
Known exploitationUnconfirmed
Based on sourced intelligence
Hinoki checkAvailable
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Summary

What happened

Authentication bypass in Traefik Proxy 3.7.0 through 3.7.2 allows remote attackers to reach mTLS-protected backends via domain fronting. SNICheck resolves the HTTP Host header through exact TLSOptions map lookups, so a wildcard host falls back to permissive default options. Exploitation requires a wildcard router with stricter TLSOptions and another permissive SNI on the same entrypoint; the result is unauthorized backend access.

The record

CVE
CVE-2026-48491
Published
Jun 23, 2026
Updated
Jun 23, 2026
Vendor
Traefik Labs
Product
Traefik Proxy
Classifications
CWE-807, CWE-288, T1190
Attack vector
network
Privileges
unauthenticated

Timeline

How it unfolded

  1. Jun 23, 2026CVE publishedPublication date reported by the CVE source.
  2. Jun 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=>= 3.7.0, < 3.7.3

What conditions does exploitation require?

Attack vectornetwork
Required privilegesunauthenticated

What is affected?

Traefik Labs · Traefik Proxyversion=>= 3.7.0, < 3.7.3

Published CVSS scores

9.1redhat-SADPCVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:H/I:H/A:N
7.8GitHub, Inc.CVSS:4.0/AV:N/AC:L/AT:N/PR:N/UI:N/VC:N/VI:N/VA:N/SC:H/SI:H/SA:N
10.0NIST NVDCVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:C/C:H/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.

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 exploitPublished

Weakness, pattern, technique

CWE-807Reliance on Untrusted Inputs in a Security Decision
CWE-288Authentication Bypass Using an Alternate Path or Channel
T1190Exploit Public-Facing Application

Public exploit references

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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