Package Instance

Werkzeug safe_join not safe on Windows
On Python < 3.11 on Windows, `os.path.isabs()` does not catch UNC paths like `//server/share`. Werkzeug's `safe_join()` relies on this check, and so can produce a path that is not safe, potentially allowing unintended access to data. Applications using Python >= 3.11, or not using Windows, are not vulnerable.

Werkzeug safe_join() allows Windows special device names with compound extensions
Werkzeug's `safe_join` function allows path segments with Windows device names that have file extensions or trailing spaces. On Windows, there are special device names such as `CON`, `AUX`, etc that are implicitly present and readable in every directory. Windows still accepts them with any file extension, such as `CON.txt`, or trailing spaces such as `CON `.

This was previously reported as https://github.com/pallets/werkzeug/security/advisories/GHSA-hgf8-39gv-g3f2, but the fix failed to account for compound extensions such as `CON.txt.html` or trailing spaces. It also missed some additional special names.

`send_from_directory` uses `safe_join` to safely serve files at user-specified paths under a directory. If the application is running on Windows, and the requested path ends with a special device name, the file will be opened successfully, but reading will hang indefinitely.

Werkzeug safe_join() allows Windows special device names
Werkzeug's `safe_join` function allows path segments with Windows device names. On Windows, there are special device names such as `CON`, `AUX`, etc that are implicitly present and readable in every directory. `send_from_directory` uses `safe_join` to safely serve files at user-specified paths under a directory. If the application is running on Windows, and the requested path ends with a special device name, the file will be opened successfully, but reading will hang indefinitely.

Pallets Werkzeug vulnerable to Path Traversal
In Pallets Werkzeug before 0.15.5, SharedDataMiddleware mishandles drive names (such as C:) in Windows pathnames.

Werkzeug safe_join() allows Windows special device names
Werkzeug's `safe_join` function allows Windows device names as filenames if when preceded by other path segments.

This was previously reported as https://github.com/pallets/werkzeug/security/advisories/GHSA-hgf8-39gv-g3f2, but the added filtering failed to account for the fact that `safe_join` accepts paths with multiple segments, such as `example/NUL`.

`send_from_directory` uses `safe_join` to safely serve files at user-specified paths under a directory. If the application is running on Windows, and the requested path ends with a special device name, the file will be opened successfully, but reading will hang indefinitely.