Werkzeug safe_join() allows Windows special device names

[ Description ]Official description

Werkzeug is a comprehensive WSGI web application library. Prior to 3.1.9, the safe_join function used by send_from_directory can allow a NUL: special-device path because safe_join checks the Windows device name without first removing an empty NTFS ADS marker. The trigger is that an application runs on Windows with NTFS and serves a user-specified path ending in a special device name such as NUL:. The attack mechanism is that a requested path ends in a Windows special device name with an empty ADS marker. The impact is that the special device opens successfully and the file read hangs indefinitely. This issue is fixed in version 3.1.9.

[ Fixes ]Fixes and patches

• Werkzeug 3.1.9Fixed version · GitHub Advisories · pip package Werkzeug: upgrade to 3.1.9 or later (affected < 3.1.9)

[ Packages ]Affected open-source packages

• Werkzeug pipAffected < 3.1.9 · fixed in 3.1.9 · GHSA-g6x2-hccm-hh4m

[ References ]References

• github.com/pallets/werkzeug/commit/8d77320bcdf3a34941ec06dcf16b03c065cd21b6
• github.com/pallets/werkzeug/pull/3309
• github.com/pallets/werkzeug/releases/tag/3.1.9
• github.com/pallets/werkzeug/security/advisories/GHSA-g6x2-hccm-hh4m