Vulnerability in Czlonkowski N8n-Mcp
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.
Published · last modified .
CVSS v3 metric
CVSS v3 base score 8.1 (High). Vector: CVSS:3.1/AV:N/AC:L/PR:L/UI:N/S:U/C:H/I:H/A:N.
EPSS exploit prediction
EPSS: 0.004 (33.0th percentile), scored .
Very low probability of exploitation in the next 30 days; routine patching cadence is appropriate. 33rd percentile — 33.0% of CVEs in the catalogue have a lower EPSS than this one. How to read EPSS.
EPSS over last 30 days · oldest: 0.002 · newest: 0.004 · change: +0.002
Affected products
- Czlonkowski N8n-Mcp — versions < 2.51.2
- N8n-Mcp
Weakness classification (CWE)
References
- github.com/czlonkowski/n8n-mcp/security/advisories/GHSA-jxx9-px88-pj69 (Mitigation, Vendor Advisory)
- github.com/czlonkowski/n8n-mcp/commit/853015d0897be7cf2d9d4726de195c938e4395ab (Patch)
- github.com/czlonkowski/n8n-mcp/releases/tag/v2.51.2 (Product, Release Notes)
Frequently asked questions
- What is CVE-2026-45707?
- CVE-2026-45707 is a high-severity vulnerability in Czlonkowski N8n-Mcp, classified under Improper Access Control. CVSS score: 8.1/10. Published 2026-05-29.
- How severe is CVE-2026-45707?
- High severity. CVSS v3 base score is 8.1 out of 10.