Auth bypass in Czlonkowski N8n-Mcp
CVE-2026-54052
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.
Vulnerability class: IDOR (Insecure Direct Object Reference)
Published · last modified .
CVSS v3 metric
CVSS v3 base score 9.9 (Critical). Vector: CVSS:3.1/AV:N/AC:L/PR:L/UI:N/S:C/C:H/I:H/A:L.
EPSS exploit prediction
EPSS: 0.004 (31.8th percentile), scored .
Very low probability of exploitation in the next 30 days; routine patching cadence is appropriate. 32nd percentile — 31.8% of CVEs in the catalogue have a lower EPSS than this one. How to read EPSS.
EPSS over last 30 days · oldest: 0.004 · newest: 0.004 · change: 0.000
Affected products
- Czlonkowski N8n-Mcp — versions < 2.56.1
- N8n-Mcp
Weakness classification (CWE)
References
- github.com/czlonkowski/n8n-mcp/security/advisories/GHSA-j6r7-6fhx-77wx (Mitigation, Vendor Advisory)
- github.com/czlonkowski/n8n-mcp/releases/tag/v2.56.1 (Release Notes)
Frequently asked questions
- What is CVE-2026-54052?
- CVE-2026-54052 is a critical-severity vulnerability in Czlonkowski N8n-Mcp, classified under Authorization Bypass Through User-Controlled Key. CVSS score: 9.9/10. Published 2026-07-15.
- How severe is CVE-2026-54052?
- Critical severity. CVSS v3 base score is 9.9 out of 10.