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Workflow telemetry sanitizer could retain partial values from URL-shaped node parameters

Moderate
czlonkowski published GHSA-f3rg-xqjj-cj9w May 11, 2026

Package

npm n8n-mcp (npm)

Affected versions

< 2.51.3

Patched versions

2.51.3

Description

Summary

In affected versions of n8n-mcp, the workflow telemetry sanitizer could retain partial fragments of URL-shaped node parameters before sending workflow data to the project's anonymous telemetry backend. Values placed in HTTP-Request-style node parameters — such as customer or tenant identifiers, short secrets embedded in query strings, and signed request parameters — could therefore appear in stored telemetry, contrary to the collection boundary documented in PRIVACY.md.

Impact

Operators with access to the project's telemetry backend could read partial fragments of workflow URL parameters that should not have been collected. The bug was scoped to URL-shaped fields in workflow definitions; credentials, OAuth tokens, and workflow execution data are not affected — credentials are removed by a separate code path, and long secrets and known-provider tokens are matched by dedicated patterns.

Patches

Fixed in n8n-mcp 2.51.3. Upgrading is the recommended remediation.

Workarounds

For users who cannot upgrade immediately, disable anonymous telemetry by setting any of these environment variables to true:

  • N8N_MCP_TELEMETRY_DISABLED
  • TELEMETRY_DISABLED
  • DISABLE_TELEMETRY

Credit

Reported by @u-ktdi.

Severity

Moderate

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
Low
Privileges required
Low
User interaction
None
Scope
Unchanged
Confidentiality
High
Integrity
None
Availability
None

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:L/PR:L/UI:N/S:U/C:H/I:N/A:N

CVE ID

CVE-2026-45582

Weaknesses

Insertion of Sensitive Information Into Sent Data

The code transmits data to another actor, but a portion of the data includes sensitive information that should not be accessible to that actor. Learn more on MITRE.

Credits