CVE-2026-45707 json
n8n-MCP: Multi-tenant MCP requests fall back to process-level n8n credentials when tenant headers are absent or incomplete
published 2026-05-18 5 mo ago modified 2026-07-21 3 mo ago also GHSA-jxx9-px88-pj69 , EUVD-2026-33318
- cvss
- 8.1
- version 3.1, CNA
- cisa kev
- Not listed
- not in CISA's catalog
- epss
- 0.2%
- EPSS 0.2% chance of exploitation in 30 days, percentile 14%
- public exploits
- 0
- none known
Summary
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.
Patch / fix
- npm n8n-mcp 2.51.2
- n8n-mcp n8n-mcp 2.51.2
CISA SSVC
- Exploitation
- none
- Automatable
- no
- Technical impact
- partial
- Assessed
- 5 mo ago
Exploit prediction
0.24% chance of exploitation in the next 30 days, higher than 14% of all scored CVEs (FIRST EPSS, 2026-11-08).
CVSS scores
| assigned by | version | score | vector |
|---|---|---|---|
| CNA | 3.1 | 8.1 | CVSS:3.1/AV:N/AC:L/PR:L/UI:N/S:U/C:H/I:H/A:N |
| GitHub | 3.1 | 8.1 | CVSS:3.1/AV:N/AC:L/PR:L/UI:N/S:U/C:H/I:H/A:N |
Affected packages
| ecosystem | package | affected | fixed in |
|---|---|---|---|
| npm | n8n-mcp | <2.51.2 |
2.51.2 |
Affected products
- czlonkowski n8n-mcp
Classification
- Weakness
-
- CWE-284 Improper Access Control
References
-
github.com
/czlonkowski/n8n-mcp/commit/853015d0897be7cf2d9d4726de195c938e4395ab
web, patch
-
github.com
/czlonkowski/n8n-mcp/security/advisories/GHSA-jxx9-px88-pj69
web, mitigation, vendor-advisory
-
github.com
/czlonkowski/n8n-mcp/releases/tag/v2.51.2
web, product, release-notes
-
nvd.nist.gov
/vuln/detail/CVE-2026-45707
advisory
-
github.com
/czlonkowski/n8n-mcp
package
Sources
- CVE List CVE-2026-45707
- GitHub Advisory GHSA-jxx9-px88-pj69
- NVD CVE-2026-45707
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