CVE-2026-104120 describes a server-side request forgery vulnerability in the fetch_url function of the Fetch Tool component within modelcontextprotocol mcp-server-fetch and mcp-server-everything up to version 2026.6.4. The vulnerability arises from improper validation of the url/path argument, enabling remote attackers to induce the server to perform unauthorized requests. The vulnerability is publicly disclosed, and a fix is pending acceptance of a pull request. No official patch or remediation has been released at this time.

Successful exploitation could allow an attacker to cause the vulnerable server to make arbitrary requests, potentially leading to information disclosure, interaction with internal systems, or other impacts associated with SSRF vulnerabilities. The CVSS score of 7.3 reflects a medium severity with impacts on confidentiality, integrity, and availability.

Currently, no official patch or fix has been released. A pull request addressing the vulnerability is awaiting acceptance. Users should monitor the vendor's repository or advisory channels for the official fix and apply it promptly once available. Until then, consider restricting network access or implementing filtering controls to limit the server's ability to make arbitrary outbound requests if feasible.