CVE-2021-21241

high
Published 2021-01-11 · Modified 2023-11-08
CVSS v3
CVSS:3.1/AV:N/AC:L/PR:N/UI:R/S:C/C:H/I:N/A:N
CVSS v2
VIR risk
8.0

Description

The Python "Flask-Security-Too" package is used for adding security features to your Flask application. It is an is a independently maintained version of Flask-Security based on the 3.0.0 version of Flask-Security. 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.

Predictions

Exploit likelihood
30%
Patch ETA

Heuristic predictions, AS-IS, for prioritization only.

Mitigations

vendor Authored 2026-05-27

Vendor advisory: debian — https://security-tracker.debian.org/tracker/CVE-2021-21241

vendor Authored 2026-05-27

Vendor advisory: suse — https://www.suse.com/security/cve/CVE-2021-21241.html

vendor Authored 2026-05-27

Vendor advisory: arch — https://security.archlinux.org/ASA-202105-2

OS impact

OSVersionStatusFixed in
arch archfixed4.0.1-1
suse slesaffected
debian debianbookwormfixed4.0.0-1
debian debianbullseyefixed4.0.0-1
debian debianforkyfixed4.0.0-1
debian debiansidfixed4.0.0-1
debian debiantrixiefixed4.0.0-1

Package impact

EcosystemPackageVulnerableFixed
python PyPIflask-security-too>=3.3.0,<3.4.53.4.5
python PyPIflask-security-too<6d50ee9169acf813257c37b75babe9c28e83542a||>=3.3.0,<3.4.561d313150b5f620d0b800896c4f2199005e84b1f

References

Verify integrity in audit chain (admin only). AS-IS.