CVE-2026-121966
Published:November 04, 2026
Updated:November 05, 2026
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.
Affected Packages
https://github.com/traefik/traefik.git (GITHUB):
Affected version(s) >=v3.0.0-beta1 <v3.7.16Fix Suggestion:
Update to version v3.7.16https://github.com/traefik/traefik.git (GITHUB):
Affected version(s) >=v2.0.0-alpha1 <v2.11.60Fix Suggestion:
Update to version v2.11.60github.com/traefik/traefik/v3 (GO):
Affected version(s) >=v3.0.0-beta1 <v3.7.16Fix Suggestion:
Update to version v3.7.16github.com/traefik/traefik/v2 (GO):
Affected version(s) >=v2.0.0-alpha1 <v2.11.60Fix Suggestion:
Update to version v2.11.60Related Resources (4)
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Contact UsCVSS v4
Base Score:
7
Attack Vector
NETWORK
Attack Complexity
LOW
Attack Requirements
PRESENT
Privileges Required
NONE
User Interaction
NONE
Vulnerable System Confidentiality
NONE
Vulnerable System Integrity
NONE
Vulnerable System Availability
NONE
Subsequent System Confidentiality
HIGH
Subsequent System Integrity
HIGH
Subsequent System Availability
NONE
CVSS v3
Base Score:
8.7
Attack Vector
NETWORK
Attack Complexity
HIGH
Privileges Required
NONE
User Interaction
NONE
Scope
CHANGED
Confidentiality
HIGH
Integrity
HIGH
Availability
NONE
Weakness Type (CWE)
Exposure of Data Element to Wrong Session