This vulnerability exists in the fetch_url function of the Fetch Tool component in modelcontextprotocol's mcp-server-fetch and mcp-server-everything products up to version 2026.6.4. Manipulation of the URL or path argument can lead to server-side request forgery, enabling an attacker to cause the server to make arbitrary requests. The vulnerability is remotely exploitable and has been publicly disclosed. A pull request containing a fix is pending acceptance, indicating no official patch is currently available.

Successful exploitation allows an unauthenticated remote attacker to induce the vulnerable server to make arbitrary HTTP requests, potentially accessing internal resources or services not otherwise accessible. This can lead to information disclosure or other impacts depending on the internal network environment. The CVSS 4.0 score of 6.9 reflects a medium severity with low attack complexity and no required privileges or user interaction.

No official patch or fix is currently available as the pull request to address the issue awaits acceptance. Users should monitor the vendor's repository or advisory channels for the official fix. Until then, consider restricting network access to the affected service or implementing network-level controls to limit outbound requests from the server to trusted destinations only.