cvedb.io
CVE-2026-27199
MEDIUM · CVSS 5.3
EPSS exploitation probability: 0%
Published 2026-02-21T06:17:00.710 · Last modified 2026-06-17T10:26:50.207

Summary

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.

Affected products

palletsprojects — werkzeug

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References

This product uses data from the NVD API but is not endorsed or certified by the NVD. Informational only; not professional security advice.