PYSEC-2026-4312

Werkzeug safe_join() allows Windows special device names

En bref

Publiée
Mise à jour
CVE
CVE-2026-102598
Alias
GHSA-g6x2-hccm-hh4m
CVSS_V4
CVSS:4.0/AV:N/AC:L/AT:P/PR:N/UI:N/VC:N/VI:N/VA:L/SC:N/SI:N/SA:N

Description

Werkzeug's `safe_join` function allows Windows device names as filenames when they have an empty ADS marker on NTFS. 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 Windows allows special device names with an empty ADS marker, such as `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 NTFS, and the requested path ends with a special device name, the file will be opened successfully, but reading will hang indefinitely.

Paquets affectés

PaquetVersions
PyPI · werkzeugintroduced 0, fixed 3.1.9

Références

Sources

SourceLicence
OSV.devCC-BY 4.0 — PyPA Advisory Database