CVE-2021-23385

low-risk
Published 2022-08-02

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.

Do I need to act?

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0.18% chance of exploitation
EPSS score — low exploit probability
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Not on CISA KEV list
No confirmed active exploitation reported to CISA
?
Patch status unknown
Check vendor advisories for fix availability and mitigation guidance
5
CVSS 5.4/10 Medium
NETWORK / LOW complexity

Affected Products (1)

Affected Vendors

Flask-Security Project

References (8)

Product https://github.com/mattupstate/flask-security
https://lists.debian.org/debian-lts-announce/2023/08/msg00034.html
Exploit https://security.snyk.io/vuln/SNYK-PYTHON-FLASKSECURITY-1293234
Technical Description https://snyk.io/blog/url-confusion-vulnerabilities/
Product https://github.com/mattupstate/flask-security
https://lists.debian.org/debian-lts-announce/2023/08/msg00034.html
Exploit https://security.snyk.io/vuln/SNYK-PYTHON-FLASKSECURITY-1293234
Technical Description https://snyk.io/blog/url-confusion-vulnerabilities/
27
/ 100
low-risk
Severity 21/34 · High
Exploitability 1/34 · Minimal
Exposure 5/34 · Minimal