🛡️ CVE-2021-23385 on Debian — flask-security

⚪ Unknown ✅ No Known Exploit OSV
N/A
CVSS Score
0 Low4 Medium7 High9 Critical10

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.

Distribution advisory

This page covers CVE-2021-23385 as tracked by Debian, for the package flask-security. The fix is available in version 5.0.2-1; earlier versions remain affected.

How this vulnerability can be exploited

This issue can be reached over the network, attack complexity is low, an attacker needs no privileges on the target. A user must be tricked into taking some action. The scope is changed, meaning a successful attack can affect components beyond the vulnerable one. Rated impact: confidentiality low, integrity low, availability none.

Weakness class

DEBIAN-CVE-2021-23385 is classified as CWE-601: Open Redirect. A redirect target is taken from user input, so a trusted link can send the visitor to an attacker's site.

Affected software

DEBIAN-CVE-2021-23385 is recorded against 1 package.

  • flask-security (fixed in 5.0.2-1)

Timeline and source

Published on 2 August 2022 and last revised on 4 August 2026. No public exploit is currently recorded for this entry. Record sourced from OSV.

References

security-tracker.debian.org (Advisory)

CVE-2021-23385 on other distributions

Each distribution ships its own build and its own fixed version. Pick the one you run:

Details

Severity Unknown
CVSS Score N/A
CVSS Vector CVSS:3.1/AV:N/AC:L/PR:N/UI:R/S:C/C:L/I:L/A:N
CWE N/A
Public Exploit ✅ No
Source OSV
Published 2022-08-02
Updated 2026-08-12
Modified 2026-08-04
Fix URL N/A

Affected Packages

Software From version Fixed in
flask-security — 5.0.2-1

Similar Threats

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