Server-Side Request Forgery Vulnerability in ModelContextProtocol's Fetch Tool
CVE-2026-104120

6.9MEDIUM

Key Information:

Vendor

Modelcontextprotocol

Status
Mcp-server-fetch
Mcp-server-everything
Vendor
CVE Published:
2 October 2026

Badges

👾 Exploit Exists🟡 Public PoC

What is CVE-2026-104120?

A security flaw has been identified in ModelContextProtocol's Fetch Tool, affecting versions up to 2026.6.4. The vulnerability resides in the fetch_url function within the server.py file of the mcp-server-fetch and mcp-server-everything components. Attackers can manipulate the url/path argument, potentially allowing them to perform server-side request forgery (SSRF) attacks. This vulnerability can be exploited remotely, posing a significant risk to affected systems. A public disclosure of the exploit has occurred, and a pull request for a fix is currently pending acceptance.

Affected Version(s)

mcp-server-everything 2026.6.0

mcp-server-everything 2026.6.1

mcp-server-everything 2026.6.2

Exploit Proof of Concept (PoC)

PoC code is written by security researchers to demonstrate the vulnerability can be exploited. PoC code is also a key component for weaponization which could lead to ransomware.

CVE-2026-104120 - Proof of Concept

References

https://vuldb.com/vuln/412764
vdb-entrytechnical-description
https://vuldb.com/vuln/412764/cti
signaturepermissions-required
https://vuldb.com/cve/CVE-2026-104120
third-party-advisory

CVSS V4

Score:
6.9
Severity:
MEDIUM
Confidentiality:
Low
Integrity:
Low
Availability:
Low
Attack Vector:
Network
Attack Complexity:
Low
Attack Required:
None
Privileges Required:
Undefined
User Interaction:
None

Timeline

  • 🟡

    Public PoC available

  • 👾

    Exploit known to exist

  • Vulnerability published

  • Vulnerability Reserved

Credit

geochen (VulDB User)
VulDB CNA Team
.