CVE-2026-88007Public exploitNetwork attack vector

Unauthenticated impersonation via shared backend connections

Published Sep 10, 2026 · Updated Sep 10, 2026

Authentication bypass in Traefik Proxy 2.11.0 through 2.11.56 and 3.0.0 through 3.7.12 allows remote attackers to impersonate users over HTTP/3. The HTTP/3 ConnContext omits service.AddTransportOnContext, causing kerberosRoundTripper to reuse a shared backend transport instead of isolating each frontend connection. Exploitation requires HTTP/3, connection-bound NTLM or Negotiate authentication, and backend keep-alive; an unrelated client can read protected data and act as the victim.

CVSS severity9.1
Critical
EPSS probability0.33%
Next 30 days · Sep 16, 2026
Known exploitationUnconfirmed
Based on sourced intelligence
Hinoki checkNot available
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Summary

What happened

Authentication bypass in Traefik Proxy 2.11.0 through 2.11.56 and 3.0.0 through 3.7.12 allows remote attackers to impersonate users over HTTP/3. The HTTP/3 ConnContext omits service.AddTransportOnContext, causing kerberosRoundTripper to reuse a shared backend transport instead of isolating each frontend connection. Exploitation requires HTTP/3, connection-bound NTLM or Negotiate authentication, and backend keep-alive; an unrelated client can read protected data and act as the victim.

The record

CVE
CVE-2026-88007
Published
Sep 10, 2026
Updated
Sep 10, 2026
Vendor
Traefik Labs
Product
Traefik Proxy
Classifications
CWE-863, CWE-287, T1190
Attack vector
network
Privileges
unauthenticated

Timeline

How it unfolded

  1. Sep 10, 2026CVE publishedPublication date reported by the CVE source.
  2. Sep 10, 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=>= 2.11.0, < 2.11.57
  2. Affected versionversion=>= 3.0.0, < 3.7.13

What conditions does exploitation require?

Attack vectornetwork
Required privilegesunauthenticated

What is affected?

Traefik Labs · Traefik Proxyversion=>= 2.11.0, < 2.11.57; version=>= 3.0.0, < 3.7.13

Published CVSS scores

9.1GitHub Security AdvisoryCVSS:4.0/AV:N/AC:L/AT:P/PR:N/UI:N/VC:H/VI:H/VA:N/SC:N/SI:N/SA: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-863Incorrect Authorization
CWE-287Improper Authentication
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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