Werkzeug safe_join() allows Windows special device names

TRUNG BÌNH 5.3CVE-2026-27199 · GHSA-29vq-49wr-vm6x · PYSEC-2026-2320 · Công bố 21/02/2026 · cập nhật 17/06/2026

Tóm tắt nhanh

CVE-2026-27199 là lỗ hổng mức TRUNG BÌNH (CVSS 5.3) ảnh hưởng werkzeug, werkzeug (palletsprojects).
Xác suất bị khai thác trong 30 ngày tới (EPSS): 0.63%, cao hơn 50.3% các lỗ hổng khác.
Cách xử lý: cập nhật lên 3.1.6 hoặc mới hơn.

Gói / sản phẩm	Phiên bản bị ảnh hưởng	Phiên bản đã vá
werkzeug PyPI	`< 3.1.6`	`3.1.6`
werkzeug palletsprojects	`< 3.1.6`	`3.1.6`

Mô tả

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.

Mô tả của NVD

Werkzeug is a comprehensive WSGI web application library. Versions 3.1.5 and below, the safe_join function allows Windows device names as filenames if preceded by other path segments. This was previously reported as 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. The function 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. This issue has been fixed in version 3.1.6.