The NetBox MCP Server exposes all NetBox data on its HTTP transport without any authentication. A client that can reach the port can initiate a valid MCP session and readfully obtain data from the four NetBox tools. This constitutes a confidentiality breach, allowing an attacker to obtain all read‑only information the server is configured to expose.

The affected product is NetBox MCP Server from netboxlabs. Versions prior to 1.2.1 are vulnerable because the HTTP endpoint lacks authentication. The patch was released in v1.2.1 and later versions are not affected.

The CVSS score of 5.9 indicates moderate severity, and the EPSS score is not available. Because the flaw is remotely exploitable from any client that can reach the port and requires no special credentials or privileges, the likelihood of exploitation is high in environments where the endpoint is exposed. The issue is not listed in the CISA KEV catalog, but the absence of authentication makes it a high risk for organizations that inadvertently expose the MCP server to the internet or untrusted internal networks.