SSRF Vulnerability in Model Context Protocol mcp-rdf-explorer

CVE-2026-19753 is a server-side request forgery (SSRF) vulnerability affecting the mcp-rdf-explorer component (version 1.0.0) of the Model Context Protocol MCP Server. The flaw resides in the 'explore_url' function located in 'src/mcp-rdf-explorer/server.py'. An unauthenticated, remote attacker can manipulate the 'url' argument passed to this function to bypass internal security controls and force the application to make arbitrary HTTP requests. This vulnerability is of high concern because it permits potential interaction with internal services or metadata endpoints not intended for public access. As of August 2026, the exploit is public and the vendor has not provided a patch.

Attack Chain

1. Attacker identifies an internet-facing service running the vulnerable mcp-rdf-explorer 1.0.0 component.
2. Attacker crafts a malicious request containing a controlled URI within the 'url' argument parameter.
3. The request is sent to the MCP server's application endpoint associated with the 'explore_url' function.
4. The application receives the input and fails to validate or sanitize the URI before passing it to the internal request handler.
5. The server executes a backend request to the attacker-supplied destination.
6. The response from the internal service or external target is processed or returned to the attacker.
7. Attacker successfully performs SSRF to exfiltrate internal metadata or interact with unreachable network segments.

Impact

Successful exploitation of this vulnerability allows an attacker to perform unauthorized actions on behalf of the server, potentially exposing internal-only network resources or credentials. Given the nature of SSRF, this may lead to further lateral movement within the environment, scanning of internal infrastructure, or unauthorized access to cloud metadata services.

Recommendation

• Immediately restrict access to the mcp-rdf-explorer server component by placing it behind a reverse proxy or VPN, ensuring it is not exposed to the public internet.
• Implement egress filtering at the network level for the server host to prevent the application from making requests to sensitive internal subnets or local loopback addresses.
• Monitor logs for unusual HTTP traffic patterns originating from the server host, specifically looking for attempts to scan internal CIDR blocks.
• Review all deployments of mcp-rdf-explorer 1.0.0 for potential indicators of exploitation or unauthorized usage until a patch is available.