CVE-2026-121966
Traefik before 2.11.60 and 3.7.16 ForwardAuth NTLM/Negotiate Identity Leak
CVSS Score
8.7
EPSS Score
0.0%
EPSS Percentile
0th
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.
| CWE | CWE-488 |
| Vendor | traefik |
| Product | traefik |
| Published | Nov 4, 2026 |
| Last Updated | Nov 4, 2026 |
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CVSS v3 Breakdown
CVSS:3.1/AV:N/AC:H/PR:N/UI:N/S:C/C:H/I:H/A:N Attack Vector
Network
Attack Complexity
High
Privileges Required
None
User Interaction
None
Scope
Changed
Confidentiality
High
Integrity
High
Availability
None
Affected Versions
traefik / traefik
0 < 2.11.60
traefik / traefik
3.0.0 < 3.7.16
References
Credits
mosafariuk