medium5.4
CVE-2021-23401
Open Redirect in Flask-User
Impact
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 backslashes 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`.
Affected packages
| Ecosystem | Package | Affected | Fixed in |
|---|---|---|---|
| pip | Flask-User | <= 1.0.2.2 | none recorded |
Affected products
| Vendor | Product | Affected versions |
|---|---|---|
| Flask-User Project | Flask-User | All versions |
Weakness classification
References
- NVD record
- CVE.org record
- GitHub advisory
- https://github.com/lingthio/Flask-User
- https://github.com/lingthio/Flask-User/blob/master/flask_user/user_manager__utils.py
- https://snyk.io/vuln/SNYK-PYTHON-FLASKUSER-1293188
- https://github.com/advisories/GHSA-4298-89hc-6rfv
- https://nvd.nist.gov/vuln/detail/CVE-2021-23401
- https://github.com/pypa/advisory-database/tree/main/vulns/flask-user/PYSEC-2021-337.yaml