file_picker (aka flutter_file_picker) for Flutter, all versions through 10.3.10, is vulnerable to path traversal (CWE-22) in its Android implementation. The openFileStream() method in FileUtils.kt uses the DISPLAY_NAME obtained from ContentResolver.query() directly in file path construction without sanitization. A malicious Android app with a crafted ContentProvider can return a filename containing ../ sequences, causing the plugin to create arbitrary files and directories outside the intended cache directory within the victim app's internal storage. Existing files are not overwritten due to an existence check.