CVE-2021-23385

MEDIUM

Flask-Security - Open Redirect via Backslash URL Validation Bypass

Title source: llm
STIX 2.1

Description

This affects all versions of package Flask-Security. When using the get_post_logout_redirect and get_post_login_redirect functions, 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. 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. **Note:** Flask-Security is not maintained anymore.

References (4)

Core 4
Core References
Product, Third Party Advisory
https://github.com/mattupstate/flask-security
Technical Description, Third Party Advisory
https://snyk.io/blog/url-confusion-vulnerabilities/

Scores

CVSS v3 5.4
EPSS 0.0089
EPSS Percentile 54.8%
Attack Vector NETWORK
CVSS:3.1/AV:N/AC:L/PR:N/UI:R/S:U/C:L/I:L/A:N

Details

CWE
CWE-601
Status published
Products (2)
flask-security_project/flask-security
pypi/Flask-Security 0PyPI
Published Aug 02, 2022
Tracked Since Feb 18, 2026