CVE-2026-45707 n8n-MCP: Multi-tenant MCP requests fall back to process-level n8n credentials when tenant headers are absent or incomplete
Authenticated tenants can access operator credentials and execute management calls on the operator's n8n instance if tenant headers are missing in multi-tenant mode.
- Exploited in the wild
- Not known
- Login needed
- Any signed-in user
- Attackable
- Over the internet
- Victim action needed
- Not needed
- Fix
- Available
What is CVE-2026-45707?
CVE-2026-45707 is a high-severity missing authorization vulnerability in czlonkowski n8n-mcp, published on 29 May 2026. Any signed-in user can exploit it over the network, with no action from the victim.
Official description
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.
Weakness: CWE-284
Which versions are affected by CVE-2026-45707?
2 open source packages ship an affected version, including n8n-mcp. It affects 1 product.
| Package | Affected | Fixed in |
|---|---|---|
n8n-mcp npm | All versions | 2.51.2 |
n8n-mcp npm | All versions | 2.51.2 |
Products include N8n-Mcp N8n-Mcp.
How do I fix CVE-2026-45707?
Upgrade n8n-mcp to 2.51.2 or later.
Upgrade, and check permissions on every request on the server, not only in the interface. More about Missing authorization.
Is CVE-2026-45707 being exploited?
There is no known exploitation of CVE-2026-45707 in the wild and no public exploit code.
Other vulnerabilities in czlonkowski n8n-mcp
- CVE-2026-54052 n8n-MCP: Cross-tenant access to workflow version backups in multi-tenant HTTP deployments
- CVE-2026-42449 n8n-MCP: IPv4-mapped IPv6 addresses bypass SSRF protection in validateUrlSync(), enabling full SSRF for SDK embedders
- CVE-2026-39974 n8n-MCP has an Authenticated SSRF via instance-URL header in multi-tenant HTTP mode
- CVE-2026-44694 n8n-MCP: Authenticated SSRF in n8n-mcp webhook and API client paths
- CVE-2026-45582 n8n-MCP: Workflow telemetry sanitizer could retain partial values from URL-shaped node parameters
Sources
Also known as GHSA-jxx9-px88-pj69.