The vulnerability arises in mcp-remote’s SSE transport, where a remote attacker can exploit the eventSourceInit fetch wrapper to read sensitive information that the application is not supposed to expose. This is a CWE-200 information disclosure flaw that allows the attacker to acquire data communicated over the network without proper access controls.

The affected versions are geelen mcp-remote 0.1.18 through 0.1.38. The product is a Node.js package used to establish server‑sent events; any version in that range is vulnerable.

The CVSS score of 7.5 indicates a high severity, the EPSS score is available (< 1%), and the vulnerability is not listed in the CISA KEV catalog. Nevertheless, the flaw allows remote information disclosure via a publicly reachable transport mechanism, making it a potentially high‑impact vulnerability. Based on the description, it is inferred that attackers would need network access to the service providing the SSE events, and no authentication is required if the SSE endpoint is exposed. The lack of official exploit data means that exploitation may be low‑to‑moderate, but the sensitivity of the leaked data could be high.