Open Redirect in Flask-User Project

CVE-2021-23401

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.

Vulnerability class: Open Redirect

EPSS: 0.011 (62.7th percentile) — read the EPSS interpretation.

CVSS v3 metric

CVSS v3 base score 5.4 (Medium). Vector: CVSS:3.1/AV:N/AC:L/PR:N/UI:R/S:U/C:L/I:L/A:N.

Affected products

Weakness classification (CWE)

References

Frequently asked questions

What is CVE-2021-23401?
CVE-2021-23401 is a medium-severity vulnerability in Flask-User Project, classified under URL Redirection to Untrusted Site (Open Redirect). CVSS score: 5.4/10. Published 2021-07-05.
How severe is CVE-2021-23401?
Medium severity. CVSS v3 base score is 5.4 out of 10.