Goal Reached Thanks to every supporter — we hit 100%!

Goal: 1000 CNY · Raised: 1359 CNY

100%
Buy Us a Coffee

CVE-2025-66221— Werkzeug safe_join() allows Windows special device names

Quick assessment

Affected
pallets werkzeug
Exploitation
No confirmed in-the-wild exploitation; assess based on exposure
Recommended action
Check the vendor advisory and references for a fixed version. If immediate upgrade is impossible, restrict exposure and increase monitoring.

Werkzeug是Pallets开源的一个全面的 WSGI web 应用程序库。 Werkzeug 3.1.4之前版本存在安全漏洞，该漏洞源于safe_join函数处理Windows设备名称不当，可能导致文件读取挂起。

AI Predicted 6.5 Difficulty: Moderate EPSS 0.51% · P41

Possible ATT&CK Techniques 1 AI

T1499.002 · Service Exhaustion Flood
Get alerts for future matching vulnerabilities Log in to subscribe

I. Basic Information for CVE-2025-66221

Vulnerability Information
Have questions about the vulnerability? See if Shenlong's analysis helps!
View Shenlong Deep Dive ↗

Although we use advanced large model technology, its output may still contain inaccurate or outdated information.Shenlong tries to ensure data accuracy, but please verify and judge based on the actual situation.

Vulnerability Title
Werkzeug safe_join() allows Windows special device names
Source: CVE Program / CVE List V5
Vulnerability 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.
Source: CVE Program / CVE List V5
CVSS Information
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
Source: CVE Program / CVE List V5
Vulnerability Type
Windows设备名处理不恰当
Source: CVE Program / CVE List V5
Vulnerability Title
Werkzeug 安全漏洞
Source: CNNVD (China National Vulnerability Database)
Vulnerability Description
Werkzeug是Pallets开源的一个全面的 WSGI web 应用程序库。 Werkzeug 3.1.4之前版本存在安全漏洞，该漏洞源于safe_join函数处理Windows设备名称不当，可能导致文件读取挂起。
Source: CNNVD (China National Vulnerability Database)
CVSS Information
N/A
Source: CNNVD (China National Vulnerability Database)
Vulnerability Type
N/A
Source: CNNVD (China National Vulnerability Database)

Affected Products

Vendor Product Affected Versions CPE Subscribe
pallets werkzeug < 3.1.4 -

II. Public POCs for CVE-2025-66221

# POC Description Source Link Shenlong Link
AI-Generated POC Premium

No public POC found.

Login to generate AI POC

III. Intelligence Information for CVE-2025-66221

请登录查看更多情报信息。

Patches & Fixes for CVE-2025-66221 (1)

IV. Related Vulnerabilities

Same product: werkzeug
Same vendor: pallets
Same weakness: CWE-67

V. Comments for CVE-2025-66221

No comments yet

Leave a comment