### [CVE-2021-23401](https://cve.mitre.org/cgi-bin/cvename.cgi?name=CVE-2021-23401)
![](https://img.shields.io/static/v1?label=Product&message=Flask-User&color=blue)
![](https://img.shields.io/static/v1?label=Version&message=%3E%3D%200%20&color=brighgreen)
![](https://img.shields.io/static/v1?label=Vulnerability&message=Open%20Redirect&color=brighgreen)

### Description

This affects all versions of package Flask-User. When using the make_safe_url function, it is possible to bypass URL validation and redirect a user to an arbitrary URL by providing multiple back slashes such as /////evil.com/path or \\\evil.com/path. This vulnerability is only exploitable if an alternative WSGI server other than Werkzeug is used, or the default behaviour of Werkzeug is modified using 'autocorrect_location_header=False.

### POC

#### Reference
- https://snyk.io/vuln/SNYK-PYTHON-FLASKUSER-1293188

#### Github
No PoCs found on GitHub currently.