Sinatra before 2.2.0 does not validate that the expanded path matches public_dir when serving static files.
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{ "availability": "No subscription required", "binaries": [ { "binary_name": "ruby-rack-protection", "binary_version": "2.0.8.1-2+deb11u1build0.22.04.1" }, { "binary_name": "ruby-sinatra", "binary_version": "2.0.8.1-2+deb11u1build0.22.04.1" }, { "binary_name": "ruby-sinatra-contrib", "binary_version": "2.0.8.1-2+deb11u1build0.22.04.1" } ] }