CVE-2025-65513
📋 TL;DR
fetch-mcp v1.0.2 and earlier contains a Server-Side Request Forgery (SSRF) vulnerability that allows attackers to bypass private IP validation mechanisms. This enables unauthorized access to internal network resources that should be restricted. Systems using vulnerable versions of fetch-mcp are affected.
💻 Affected Systems
- fetch-mcp
📦 What is this software?
⚠️ Risk & Real-World Impact
Worst Case
Attackers could access sensitive internal services, exfiltrate data from internal systems, or pivot to attack other internal network resources.
Likely Case
Unauthorized access to internal APIs, metadata services, or other internal web resources accessible from the vulnerable server.
If Mitigated
Limited impact if network segmentation restricts internal resource access or if the application doesn't process user-controlled URLs.
🎯 Exploit Status
SSRF vulnerabilities are commonly exploited and public analysis is available.
🛠️ Fix & Mitigation
✅ Official Fix
Patch Version: v1.0.3 or later
Vendor Advisory: https://github.com/Team-Off-course/MCP-Server-Vuln-Analysis/blob/main/CVE-2025-65513.md
Restart Required: Yes
Instructions:
1. Update fetch-mcp to v1.0.3 or later using npm update fetch-mcp. 2. Restart any services using fetch-mcp. 3. Verify the update was successful.
🔧 Temporary Workarounds
Network-level restrictions
allImplement network firewall rules to restrict outbound connections from the vulnerable server to only necessary external resources.
Input validation enhancement
allAdd additional URL validation in application code before passing URLs to fetch-mcp.
🧯 If You Can't Patch
- Implement strict network segmentation to limit what internal resources the vulnerable server can access.
- Deploy a web application firewall (WAF) with SSRF protection rules enabled.
🔍 How to Verify
Check if Vulnerable:
Check package.json or run npm list fetch-mcp to see if version is 1.0.2 or earlier.Check Version:
npm list fetch-mcp | grep fetch-mcpVerify Fix Applied:
Confirm fetch-mcp version is 1.0.3 or later using npm list fetch-mcp.📡 Detection & Monitoring
Log Indicators:
- Unusual outbound HTTP requests from the server to internal IP addresses
- Requests to metadata services (169.254.169.254, etc.)
- Failed connection attempts to restricted internal addresses
Network Indicators:
- HTTP traffic from server to internal IP ranges not normally accessed
- Requests to localhost or loopback addresses from server processes
SIEM Query:
source="web_server_logs" AND (dst_ip IN (10.0.0.0/8, 172.16.0.0/12, 192.168.0.0/16, 127.0.0.0/8, 169.254.169.254)) AND user_agent="fetch-mcp"