CVE-2021-23401
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.
Does this matter?
Lower severity and a low EPSS score (1.11%). Track it; it rarely justifies an emergency change on its own.
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.
- CVSS 3.1
- 6.1 MEDIUMCVSS:3.1/AV:N/AC:L/PR:N/UI:R/S:C/C:L/I:L/A:N
- EPSS
- 1.11% probability · 64th percentile
- CISA KEV
- Not listed
- Weakness
- CWE-601
- Affected
- flask-user project/flask-user
- Source
- report@snyk.io
References
- https://github.com/lingthio/Flask-UserProduct, Third Party Advisory
- https://github.com/lingthio/Flask-User/blob/master/flask_user/user_manager__utils.pyExploit, Third Party Advisory
- https://snyk.io/vuln/SNYK-PYTHON-FLASKUSER-1293188Third Party Advisory
- https://github.com/lingthio/Flask-UserProduct, Third Party Advisory
- https://github.com/lingthio/Flask-User/blob/master/flask_user/user_manager__utils.pyExploit, Third Party Advisory
- https://snyk.io/vuln/SNYK-PYTHON-FLASKUSER-1293188Third Party Advisory
Source: NVD record, EPSS from FIRST.org, KEV from CISA. Refreshed daily.