CVE-2026-45707
n8n-MCP is an MCP server that provides AI assistants access to n8n node documentation, properties, and operations. Prior to 2.51.2, when ENABLE_MULTI_TENANT=true, the HTTP transport documents that the target n8n instance is selected per-request from x-n8n-url / x-n8n-key headers. Requests that omitted those headers, or supplied only one of them, silently fell back to the process-level N8N_API_URL / N8N_API_KEY credentials configured for the operator's own n8n instance.
As a result, an authenticated MCP tenant could cause n8n management calls to execute against the operator's instance instead of its own. This affects HTTP-mode deployments of n8n-mcp that are run as a shared multi-tenant service. Single-tenant deployments (ENABLE_MULTI_TENANT unset or false) are not affected.
This vulnerability is fixed in 2.51.2.
- CVSS base score ≥ 7.0
ATT&CK techniques
20Techniques this CVE enables - linked via CWECAPECATT&CK. High◆ = named directly in ATT&CK or Nuclei templates.
CAPEC attack patterns
12Attack patterns this CVE enables - the bridge from weakness to ATT&CK technique.