{"id":"CVE-2026-45707","aliases":["GHSA-jxx9-px88-pj69"],"url":"https://o3.security/vulnerability/CVE-2026-45707","summary":"n8n-MCP: Multi-tenant MCP requests fall back to process-level n8n credentials when tenant headers are absent or incomplete","details":"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":"2026-05-29T13:35:42.281Z","modified":"2026-08-12T03:51:15.462473319Z","cvss":{"score":8.1,"severity":"HIGH","vector":"CVSS:3.1/AV:N/AC:L/PR:L/UI:N/S:U/C:H/I:H/A:N"},"epss":{"score":0.00235,"percentile":0.1463,"asOf":"2026-08-14"},"cisaKev":null,"exploitsKnown":0,"affectedPackages":[{"ecosystem":"npm","name":"n8n-mcp","fixedVersion":"2.51.2"}],"fix":{"url":"https://github.com/czlonkowski/n8n-mcp/commit/853015d0897be7cf2d9d4726de195c938e4395ab","label":"czlonkowski/n8n-mcp@853015d"},"references":[{"type":"WEB","url":"https://github.com/czlonkowski/n8n-mcp/releases/tag/v2.51.2"},{"type":"ADVISORY","url":"https://github.com/CVEProject/cvelistV5/tree/main/cves/2026/45xxx/CVE-2026-45707.json"},{"type":"ADVISORY","url":"https://github.com/czlonkowski/n8n-mcp/security/advisories/GHSA-jxx9-px88-pj69"},{"type":"ADVISORY","url":"https://nvd.nist.gov/vuln/detail/CVE-2026-45707"},{"type":"FIX","url":"https://github.com/czlonkowski/n8n-mcp/commit/853015d0897be7cf2d9d4726de195c938e4395ab"}],"provenance":{"sources":["OSV.dev","FIRST.org (EPSS)"],"lastVerified":"2026-08-12T03:51:15.462473319Z"}}