VULNERABILITY INTELLIGENCE

CVE-2021-23401

CVSS score5.4 MEDIUM
EPSS probability1.11%
CISA KEVNot currently listed
Published2021-07-05
Last modified2026-06-17
CVSS vectorCVSS:3.1/AV:N/AC:L/PR:N/UI:R/S:U/C:L/I:L/A:N

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.

Weakness classification

  • nvd@nist.gov: CWE-601

Primary references