CVE-2021-23401

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.

How to fix CVE-2021-23401

No fixed version has been published yet. Mitigate by removing the affected package or applying upstream guidance from the references below.

• —no fix listed
• —no fix listed

Is CVE-2021-23401 being exploited?

Low — EPSS is 0.3%, meaning exploitation activity has not been observed at scale.

Affected packages (2)

• from 0, <= 1.0.2.2
• from 0

CVSS scores

References (6)

• ADVISORYgithub.com/advisories/GHSA-4298-89hc-6rfv
• ADVISORYnvd.nist.gov/vuln/detail/CVE-2021-23401
• PATCHgithub.com/lingthio/Flask-User
• WEBgithub.com/lingthio/Flask-User/blob/master/flask_user/user_manager__utils.py