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VulnerabilityPublished

n8n-mcp affected by path traversal, redirect-following SSRF, and telemetry payload exposure

Affects n8n-mcpSource GCVE Database

0

CVSS 8.3 High : upgrade to 2.50.1 soon.

Data as of 27 Oct 2026, 00:07 UTC

CVSS 3.1 base score
8.3High
How severe the flaw is on the 0–10 CVSS scale.
Patch
Available – fixed in 2.50.1
CVSS:3.1/AV:N/AC:L/PR:L/UI:N/S:U/C:H/I:H/A:L

What to do

Upgrade n8n-mcp to 2.50.1.

Affected software

ProductAffectedFixed in
npmn8n-mcpAffected
  • <2.50.1
Fixed in
  • 2.50.1

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Description

## Impact `n8n-mcp` versions before 2.50.1 contained three independently-reported issues affecting deployments that run the n8n API integration: 1. **Caller-supplied identifiers were not validated before being used as URL path segments** by the n8n API client. An authenticated MCP caller passing a crafted workflow id could cause outbound requests carrying the configured n8n API key to land on other same-origin endpoints, bypassing handler-level access controls (including `DISABLED_TOOLS`). 2. **Validated webhook, form, and chat trigger URLs followed redirects.** A URL that passed initial validation could redirect the outbound request to a host that would otherwise have been rejected, with the response body returned to the caller. Reachable as non-blind SSRF over authenticated MCP calls. 3. **Mutation telemetry stored unredacted operation payloads.** On instances running with the default opt-in telemetry, partial-update operation diffs were uploaded without redaction. Operation values can carry the same node-parameter values the workflow contains, including bearer tokens, API keys, and webhook secrets. ## Severity CVSS 8.3 (HIGH). Exploitation requires an authenticated MCP caller and an n8n API integration configured with an n8n API key. ## Patched versions Upgrade to `n8n-mcp >= 2.50.1`. ## Workarounds - For issues (1) and (2): restrict network access to the HTTP transport (firewall, reverse-proxy ACL, or VPN) so only trusted callers can reach the MCP HTTP port; or switch to stdio mode, which exposes no HTTP surface for these issues. - For issue (3): set `N8N_MCP_TELEMETRY_DISABLED=true` in the environment before starting the server, or run `npx n8n-mcp telemetry disable` once. ## Credit Reported by @cybercraftsolutionsllc.

References

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