Arch Linux Security Advisory ASA-202105-2
========================================
Severity: High
Date    : 2021-05-19
CVE-ID  : CVE-2021-21241
Package : python-flask-security-too
Type    : cross-site request forgery
Remote  : Yes
Link    : https://security.archlinux.org/AVG-1434

Summary
======
The package python-flask-security-too before version 4.0.1-1 is
vulnerable to cross-site request forgery.

Resolution
=========
Upgrade to 4.0.1-1.

# pacman -Syu "python-flask-security-too>=4.0.1-1"

The problem has been fixed upstream in version 4.0.1.

Workaround
=========
If you aren't using authentication tokens, you can set
SECURITY_TOKEN_MAX_AGE to "0" (seconds) which should make the token
unusable.

Description
==========
In Flask-Security-Too from version 3.3.0 and before version 3.4.5, the
/login and /change endpoints can return the authenticated user's
authentication token in response to a GET request. Since GET requests
aren't protected with a CSRF token, this could lead to a malicious 3rd
party site acquiring the authentication token. Version 3.4.5 and
version 4.0.0 are patched. As a workaround, if you aren't using
authentication tokens - you can set the SECURITY_TOKEN_MAX_AGE to "0"
(seconds) which should make the token unusable.

Impact
=====
A remote attacker could obtain a user's authentication token from a
cross-site request.

References
=========
https://bugs.archlinux.org/task/70041
https://github.com/Flask-Middleware/flask-security/security/advisories/GHSA-hh7m-rx4f-4vpv
https://github.com/Flask-Middleware/flask-security/issues/421
https://github.com/Flask-Middleware/flask-security/pull/422
https://github.com/Flask-Middleware/flask-security/commit/c05afe837e83f20f59c0fb409ce1240341d1ec41
https://security.archlinux.org/CVE-2021-21241