Open-Source Security Intelligence

Know every vulnerability
before it knows you.

DevGuard continuously monitors your dependencies and alerts you when CVEs like this one affect your stack — with real-time threat intelligence built for developers.

Checkout DevGuardView on GitHub
Search

GHSA-8g7g-hmwm-6rv2

HighCVSS 8.3 / 10
Published May 8, 2026·Last modified May 8, 2026
Affected Components(0)

No affected components available

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.

Risk Scores
Base Score
8.3

The vulnerability can be exploited over the network without needing physical access. It is easy for an attacker to exploit this vulnerability. An attacker needs basic access or low-level privileges. No user interaction is needed for the attacker to exploit this vulnerability. The impact is confined to the system where the vulnerability exists. There is a high impact on the confidentiality of the information. There is a high impact on the integrity of the data. There is a low impact on the availability of the system.

Threat Intelligence
7.6

Exploitation activity has been observed. Apply available patches or mitigations urgently.

EPSS
N/A

Probability that this vulnerability will be exploited in the wild within the next 30 days.

Exploit
Not available

We did not find any exploit available. Neither in GitHub repositories nor in the Exploit-Database.

Browse More

High severity
Scan your project

Continuously monitor your dependencies and get alerted when vulnerabilities like this one affect your stack.

Checkout DevGuard