Traefik 2.x before 2.11.60 and 3.x before 3.7.16 sends ForwardAuth subrequests (and, in 3.7, Ingress NGINX auth-url requests) through an auth-server connection pool shared by all clients, exposing connection-bound NTLM or Negotiate authentication. An unauthenticated attacker can reuse another user's authenticated connection, receiving the victim's identity via authResponseHeaders to access backends as that user.

Attack Vector Network

Attack Complexity Low

Privileges Required None

Attack Requirements Present

User Interaction None

Vulnerable System Confidentiality Impact None

Vulnerable System Integrity Impact None

Vulnerable System Availability Impact None

Subsequent System Confidentiality Impact High

Subsequent System Integrity Impact High

Subsequent System Availability Impact None

Attack Vector Network

Attack Complexity High

Privileges Required None

Scope Changed

Confidentiality Impact High

Integrity Impact High

Availability Impact None

User Interaction None

No CVSS v3.0

No CVSS v2

This CVE is not in the KEV list.

No EPSS score available.

Key SSVC decision points have not yet been added.

Default status is the baseline for the product, each version can override it (e.g. patched versions marked unaffected).

Vendor Product Default status Versions
traefik traefik unaffected
Version Status Constraints
0 affected < 2.11.60
2.11.60 unaffected —
traefik traefik unaffected
Version Status Constraints
3.0.0 affected < 3.7.16
3.7.16 unaffected —

No data.

No data.

No data.

Project Subscriptions

Vendors Products
Traefik Subscribe
Traefik Subscribe
Advisories

No advisories yet.

Fixes

Solution

No solution given by the vendor.

Workaround

No workaround given by the vendor.

References
Link Providers
https://github.com/traefik/traefik/security/advisories/GHSA-hrpp-p4fc-wwf8 cve-icon
https://www.vulncheck.com/advisories/traefik-before-2.11.60-and-3.7.16-forwardauth-ntlm-negotiate-identity-leak cve-icon
History

Wed, 04 Nov 2026 15:45:00 +0000

Type Values Removed Values Added
Description Traefik 2.x before 2.11.60 and 3.x before 3.7.16 sends ForwardAuth subrequests (and, in 3.7, Ingress NGINX auth-url requests) through an auth-server connection pool shared by all clients, exposing connection-bound NTLM or Negotiate authentication. An unauthenticated attacker can reuse another user's authenticated connection, receiving the victim's identity via authResponseHeaders to access backends as that user.
Title Traefik before 2.11.60 and 3.7.16 ForwardAuth NTLM/Negotiate Identity Leak
First Time appeared Traefik
Traefik traefik
Weaknesses CWE-488
CPEs cpe:2.3:a:traefik:traefik:*:*:*:*:*:*:*:*
Vendors & Products Traefik
Traefik traefik
References
Metrics cvssV3_1

{'score': 8.7, 'vector': 'CVSS:3.1/AV:N/AC:H/PR:N/UI:N/S:C/C:H/I:H/A:N'}

cvssV4_0

{'score': 7, 'vector': 'CVSS:4.0/AV:N/AC:L/AT:P/PR:N/UI:N/VC:N/VI:N/VA:N/SC:H/SI:H/SA:N'}

Projects

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cve-icon MITRE

Status: PUBLISHED

Assigner: VulnCheck

Published:

Updated: 2026-11-04T15:33:28.106Z

Reserved: 2026-11-04T12:48:39.813Z

Link: CVE-2026-121966

cve-icon Vulnrichment

No data.

cve-icon NVD

No data.

cve-icon Redhat

No data.

cve-icon OpenCVE Enrichment

No data.

Weaknesses