CVE-2026-102598

UNKNOWN 0.0

Werkzeug safe_join() allows Windows special device names

CVSS Score

0.0

EPSS Score

0.0%

EPSS Percentile

0th

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.

CWE	CWE-67
Vendor	pallets
Product	werkzeug
Published	Sep 29, 2026
Last Updated	Sep 29, 2026

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Affected Versions

pallets / werkzeug

< 3.1.9

References

NVD ↗ CVE.org ↗ EPSS Data ↗

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