fix: prevent command injection in example URL opening#1553
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fix: prevent command injection in example URL opening#1553
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Replace exec() with execFile() and add URL scheme validation in both elicitationUrlExample.ts and simpleOAuthClient.ts. The previous code used exec() with string interpolation, which invokes a shell and allows command injection via crafted URLs containing shell metacharacters (e.g., double-quote escapes and & as command separators). Changes: - Use execFile() with array arguments instead of exec() with string interpolation to avoid shell interpretation - Add cross-platform support (open/xdg-open/start) instead of hardcoding macOS open command - Add URL scheme allowlist (http/https only) to prevent abuse via dangerous protocol handlers (file://, smb://, ms-msdt://, etc.)
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@modelcontextprotocol/client
@modelcontextprotocol/server
@modelcontextprotocol/express
@modelcontextprotocol/hono
@modelcontextprotocol/node
commit: |
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Summary
Fix a command injection issue in the example clients, mirroring the equivalent fix in the Python SDK (modelcontextprotocol/python-sdk#2082).
Problem
elicitationUrlExample.tsandsimpleOAuthClient.tsusedexec()with string interpolation to open URLs in the browser:exec()spawns a shell, so a crafted URL can break out of the quotes and execute arbitrary commands. The original code also hardcodedopen, which only works on macOS.Fix
exec/execFilewith theopenpackage, which handles cross-platform browser opening safely (macOS, Windows, Linux, WSL) without shell invocationhttp:,https:) with propertry/catcharoundnew URL()child_processimportsThe
openpackage is added only to theexamples/clientpackage ("private": true, never published to npm), not to the SDK itself.AI Disclaimer