CVE-2026-42449
HighCVSS 8.5Exploitation Probability (EPSS)
Low risk11th percentile - higher than 11% of all known CVEs
Summary
n8n-MCP versions 2.47.4 through 2.47.13 have an incomplete URL validator in SSRFProtection.validateUrlSync() that lacks IPv6 checks. IPv4-mapped IPv6 addresses such as http://[::ffff:169.254.169.254] bypass cloud-metadata, localhost, and private-IP range checks, allowing an attacker to make the server issue requests to sensitive targets and return responses plus the x-n8n-api-key header. The issue is fixed in version 2.47.14.
Risk Assessment
An attacker could reach cloud metadata, local services, and private networks and capture the n8n API key, potentially leading to privilege escalation and data leakage. The risk applies to deployments embedding n8n-mcp as an SDK with user-supplied InstanceContext.
Recommendation
Upgrade n8n-MCP to version 2.47.14 or later. As a workaround, validate URLs before passing them to the SDK, restrict egress at the network layer, and reject user-controlled n8nApiUrl values.
Other vulnerabilities in n8n-MCP
See all- CVE-2026-54052Critical
In n8n-MCP prior to version 2.56.1, in HTTP mode with multi-tenancy enabled (ENABLE_MULTI_TENANT=true), local workflow version history backups were not isolated per tenant. This allowed an authenticated tenant to read and delete backups of other tenants, including full node definitions, credential references, and authorization headers.
- CVE-2026-44694Critical
n8n-MCP, an MCP server, has an authenticated server-side request forgery vulnerability affecting webhook trigger tools and the n8n API client. This issue exists in versions from 2.18.7 to before 2.50.2 and has been patched in version 2.50.2.
- CVE-2026-55608Medium
In n8n-MCP prior to version 2.57.4, multi-tenant HTTP mode with ENABLE_MULTI_TENANT=true could allow an authenticated tenant to access default-scope workflow_versions backups instead of being confined to the tenant scope, exposing or deleting workflow-version backups from prior single-tenant deployments or migrations.
- CVE-2026-45707High
In n8n-MCP prior to 2.51.2, when ENABLE_MULTI_TENANT=true, HTTP requests without x-n8n-url or x-n8n-key headers silently fell back to the operator's credentials, allowing an authenticated MCP tenant to execute n8n management calls against the operator's instance instead of its own.
- CVE-2026-45582Medium
In n8n-MCP prior to 2.51.3, the workflow telemetry sanitizer could retain partial fragments of URL-shaped node parameters, such as customer identifiers or secrets in query strings, before sending data to the anonymous telemetry backend. This is fixed in version 2.51.3.
- CVE-2026-42282Medium
In n8n-MCP prior to version 2.47.13, when running in HTTP transport mode, authenticated tools/call requests had their full arguments and JSON-RPC params written to server logs before any redaction. When a tool call carries credential material (e.g., n8n_manage_credentials.data), raw values can be persisted in logs. In deployments with log collection, this can disclose bearer tokens, OAuth credentials, API keys, and other secrets. The issue requires authentication and is patched in version 2.47.13.
- CVE-2026-41495Medium
In n8n-MCP prior to version 2.47.11, when running in HTTP transport mode, request metadata for the POST /mcp endpoint was written to server logs regardless of authentication outcome. In deployments where logs are collected or forwarded, this can disclose bearer tokens, per-tenant API keys, and JSON-RPC payloads. Access control was not bypassed — unauthenticated requests were correctly rejected with 401 — but sensitive values could still be persisted in logs. The issue is patched in version 2.47.11.
Original NVD description (English source)
n8n-MCP is an MCP server that provides AI assistants access to n8n node documentation, properties, and operations. In versions 2.47.4 through 2.47.13, the SDK embedder path (N8NDocumentationMCPServer constructor, getN8nApiClient(), and validateInstanceContext()), the synchronous URL validator in SSRFProtection.validateUrlSync() had no IPv6 checks. IPv4-mapped IPv6 addresses such as http://[::ffff:169.254.169.254] bypassed the cloud-metadata, localhost, and private-IP range checks. An attacker able to supply an n8nApiUrl value could cause the server to issue HTTP requests to cloud metadata endpoints, RFC1918 private networks, or localhost services. Response bodies are returned to the caller (non-blind SSRF), and the n8nApiKey is forwarded in the x-n8n-api-key header to the attacker-controlled target. Projects with deployments embedding n8n-mcp as an SDK using N8NDocumentationMCPServer or N8NMCPEngine with user-supplied InstanceContext are affected. The first-party HTTP server deployment was not primarily affected — it has a second async validator (validateWebhookUrl) that catches IPv6 addresses. This issue has been fixed in version 2.47.14. If users are unable to upgrade immediately as a workaround they can validate URLs before passing to the SDK, restrict egress at the network layer, and reject user-controlled n8nApiUrl values.
Vulnerability data from NVD (NIST) · CISA KEV · EPSS