Medium 5.3Published Nov 29, 2025

CVE-2025-66221Werkzeug is a comprehensive WSGI web application library.

Updated under an hour ago (2026-10-19 07:23 UTC)

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It affects palletsprojects werkzeug. Add what you run to find out whether that includes you.

No exploitation reported and no EPSS estimate yet.

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Every CVE for palletsprojects werkzeug

Exploited in the last 30 days

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.

CVSS: 5.3 MEDIUM (v3.1, NVD)CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:N/I:N/A:L
Weakness (CWE): CWE-67
Known exploited: Not in CISA's KEV catalog
EPSS (exploitation in the next 30 days): Not loaded for this CVE
Assigned by: Not given
NVD analysis: Analyzed
Record last updated: Oct 7, 2026
First seen by InfoSec Signals: Oct 9, 2026

Affected products

Affected products

palletsprojects werkzeug palletsprojects:werkzeug	before 3.1.4	NVD

References

https://github.com/pallets/werkzeug/commit/4b833376a45c323a189cd11d2362bcffdb1c0c13patch
https://github.com/pallets/werkzeug/releases/tag/3.1.4release-notes
https://github.com/pallets/werkzeug/security/advisories/GHSA-hgf8-39gv-g3f2vendor-advisory

The CVE record on cve.org NVD's entry

The CVE record is authoritative. Products marked “from the name” were identified from the CNA's free-text names, not a CPE, and are matched less certainly. This product uses the NVD API but is not endorsed or certified by the NVD.