GHSA-rqgx-cvr7-hc6x: 
JavaScript vulnerability analysis and mitigation

Impact

• Telemetry: the anonymous telemetry sanitizer kept some values it should have removed. These were short API keys and signatures sent as name/value query or header parameters, secrets under secret-like keys inside JSON-string parameters, and email addresses or phone numbers in node names sent with validation results. These values could reach the n8n-mcp telemetry store.
• Logs: when a stringified object or array argument could not be parsed, a warning log line included the start of the raw argument value. This could put inline credentials from workflow parameters into the operator's logs. There is no cross-tenant access and no access to the connected n8n instance.

Affected versions

n8n-mcp 2.98.1 and earlier.

Patched versions

2.99.0.

Workarounds

• Disable telemetry with N8N_MCP_TELEMETRY_DISABLED=true.
• Set LOG_LEVEL=error to drop warning lines.
• Store secrets in n8n credentials instead of inline node parameters.

Credit

Found in an internal security review.