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CVE-2026-54052: N8n Mcp: Authorization Bypass Through User-Controlled Key

CVE-2026-54052 is rated critical with a CVSS v3.1 base score of 9.9 and affects N8n Mcp. Per its scoring, it can be exploited over the network, without any user interaction.

Vulnerability description

n8n-MCP is an MCP server that provides AI assistants access to n8n node documentation, properties, and operations. Prior to 2.56.1, in HTTP mode with multi-tenancy enabled through ENABLE_MULTI_TENANT=true, n8n-mcp's local workflow version history backups were not isolated per tenant, allowing an authenticated tenant to read workflow version snapshots belonging to other tenants and delete or destroy other tenants' stored backups, including full node definitions, credential references, and authorization headers. This issue is fixed in version 2.56.1.

Severity breakdown

CVSS v3.1 9.9: CVSS:3.1/AV:N/AC:L/PR:L/UI:N/S:C/C:H/I:H/A:L

  • Attack vector: Network. Exploitable remotely over the network, with no need for local or physical access.
  • Attack complexity: Low. No special conditions; the attack can be repeated reliably.
  • Privileges required: Low. A basic user account is enough.
  • User interaction: None. No action from any user is needed.
  • Scope: Changed. Impact reaches beyond the vulnerable component to other resources.
  • Confidentiality impact: High. Total loss of confidentiality; sensitive data can be fully disclosed.
  • Integrity impact: High. Total loss of integrity; data or system state can be fully modified.
  • Availability impact: Low. Reduced performance or intermittent interruption.

Underlying weakness

CWE-639: Authorization Bypass Through User-Controlled Key

The system's authorization functionality does not prevent one user from gaining access to another user's data or record by modifying the key value identifying the data.

CWE-862: Missing Authorization

The product does not perform an authorization check when an actor attempts to access a resource or perform an action.

Affected products

  • N8n Mcp: before 2.56.1

References