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Description

Werkzeug is a comprehensive WSGI web application library. Prior to version 3.1.4, 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. This issue has been patched in version 3.1.4.

PUBLISHED Reserved 2025-11-24 | Published 2025-11-29 | Updated 2025-11-29 | Assigner GitHub_M




MEDIUM: 6.3CVSS:4.0/AV:N/AC:L/AT:P/PR:N/UI:N/VC:N/VI:N/VA:L/SC:N/SI:N/SA:N

Problem types

CWE-67: Improper Handling of Windows Device Names

Product status

< 3.1.4
affected

References

github.com/...rkzeug/security/advisories/GHSA-hgf8-39gv-g3f2

github.com/...ommit/4b833376a45c323a189cd11d2362bcffdb1c0c13

github.com/pallets/werkzeug/releases/tag/3.1.4

cve.org (CVE-2025-66221)

nvd.nist.gov (CVE-2025-66221)

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