CVE-2026-50158

Name of the Vulnerable Software and Affected Versions yutu version 0.0.0-dev

Description An arbitrary file write issue exists in the caption-download MCP tool. The tool fails to validate, canonicalize, or confine the file parameter to the intended YUTU ROOT boundary, passing it directly to the os.Create() function. This allows a local attacker or any process capable of reaching the HTTP MCP server to write arbitrary content to any path accessible by the yutu process, bypassing the established file I/O restrictions. This can be exploited via the /mcp endpoint by providing a malicious path in the file variable within the caption-download tool arguments. Potential impacts include overwriting application binaries, configuration files, or shell startup scripts to achieve persistent code execution, as well as causing denial of service by corrupting critical files.

Recommendations For version 0.0.0-dev, replace the os.Create(c.File) call with pkg.Root.OpenFile(c.File, os.O WRONLY|os.O CREATE|os.O TRUNC, 0600) to ensure the file operation is confined to the root directory. As a temporary mitigation, restrict access to the caption-download tool or avoid using the file parameter with untrusted input until the fix is applied.