Remote Code Execution in geelen mcp-remote

Executive Summary

CVE-2026-51997 is a vulnerability in geelen mcp-remote versions 0.1.16 through 0.1.38 where incomplete URL validation allows a remote attacker to execute arbitrary code via the open() functions. The issue involves improper handling of URLs, enabling attackers to open restricted or internal URLs in a user's browser.

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Detection Guidance

Check if your system uses mcp-remote versions 0.1.16 through 0.1.38. Inspect browser launch behavior for improper URL handling. Look for unexpected browser navigation to internal or restricted URLs.

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Impact Analysis

This vulnerability could allow an attacker to interact with internal services, perform reconnaissance, or facilitate browser-mediated CSRF attacks if the target service lacks protections. Attackers might exploit it to access sensitive internal resources or execute unauthorized actions on behalf of the user.

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Mitigation Strategies

Upgrade mcp-remote to a version that includes proper URL validation. Explicitly reject loopback, private, link-local, multicast, reserved, and metadata-service addresses. Display the final origin to users before navigation.

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