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 5mo ago modified 3mo ago also EUVD-2026-33318 , GHSA-jxx9-px88-pj69
- 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
Is CVE-2026-45707 in your dependencies? Fencer shows which of your repositories are affected as soon as an advisory lands, and opens the fix as a pull request.
Check with FencerCISA SSVC
- Exploitation
- none
- Automatable
- no
- Technical impact
- partial
- Assessed
- 5mo ago
Exploit prediction
0.24% chance of exploitation in the next 30 days, higher than 14% of all scored CVEs (FIRST EPSS, 2026-11-09).
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
Fencer Intel keeps one entry per vulnerability: the CVE id wins, then GHSA, and records that alias each other are merged, except that two CVEs always keep separate entries. The same data is available as JSON.
CPEs and fixed versions use Anchore's correction of NVD's data: Added CPE configurations because not yet analyzed by NVD.