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Internal proxy auth token forwarded to backend services enables management API escalation

Critical
almeidapaulopt published GHSA-g936-7jqj-mwv8 Jun 3, 2026

Package

gomod github.com/almeidapaulopt/tsdproxy (Go)

Affected versions

<= 2.3.4

Patched versions

>= 2.3.5

Description

Fix

Fixed in commit 434819b on the v2 branch:

  1. Auth token no longer forwarded to external backends — x-tsdproxy-auth-token is now only sent when the reverse proxy target is the internal management server itself (self-proxy/dashboard case), detected via isManagementTarget() which checks the target is a loopback address on the management port. All other backends never receive the token.

  2. Identity headers guarded on authenticated users only — The WhoisFromContext check now requires user.ID != "", so unauthenticated requests (Funnel, empty Whois) no longer emit any identity headers or the auth token.

A patched release will follow.

Severity

Critical

CVSS overall score

This score calculates overall vulnerability severity from 0 to 10 and is based on the Common Vulnerability Scoring System (CVSS).
/ 10

CVSS v3 base metrics

Attack vector
Network
Attack complexity
High
Privileges required
None
User interaction
None
Scope
Changed
Confidentiality
High
Integrity
High
Availability
High

CVSS v3 base metrics

Attack vector: More severe the more the remote (logically and physically) an attacker can be in order to exploit the vulnerability.
Attack complexity: More severe for the least complex attacks.
Privileges required: More severe if no privileges are required.
User interaction: More severe when no user interaction is required.
Scope: More severe when a scope change occurs, e.g. one vulnerable component impacts resources in components beyond its security scope.
Confidentiality: More severe when loss of data confidentiality is highest, measuring the level of data access available to an unauthorized user.
Integrity: More severe when loss of data integrity is the highest, measuring the consequence of data modification possible by an unauthorized user.
Availability: More severe when the loss of impacted component availability is highest.
CVSS:3.1/AV:N/AC:H/PR:N/UI:N/S:C/C:H/I:H/A:H

CVE ID

No known CVE

Weaknesses

Exposure of Sensitive Information to an Unauthorized Actor

The product exposes sensitive information to an actor that is not explicitly authorized to have access to that information. Learn more on MITRE.

Improper Authentication

When an actor claims to have a given identity, the product does not prove or insufficiently proves that the claim is correct. Learn more on MITRE.

Credits