CVE-2021-41265

Name: CVE-2021-41265
Creator: NVD / NIST
Published: 2021-12-09T17:15:07.963+00:00
License: https://creativecommons.org/publicdomain/zero/1.0/

HIGHCVSS 8.8/10EPSS 1.25%

Last modified Jun 17, 2026

CVE-2021-41265 is a high-severity vulnerability rated 8.8/10 on the CVSS scale. Flask-AppBuilder is a development framework built on top of Flask. Verions prior to 3.3.4 contain an improper authentication vulnerability in the REST API. EPSS estimates a 1.25% chance of exploitation in the next 30 days.

Description

Flask-AppBuilder is a development framework built on top of Flask. Verions prior to 3.3.4 contain an improper authentication vulnerability in the REST API. The issue allows for a malicious actor with a carefully crafted request to successfully authenticate and gain access to existing protected REST API endpoints. This only affects non database authentication types and new REST API endpoints. Users should upgrade to Flask-AppBuilder 3.3.4 to receive a patch.

Metrics

CVSS 3.1

8.8/10

CVSS:3.1/AV:N/AC:L/PR:L/UI:N/S:U/C:H/I:H/A:H

EPSS Probability

1.25%

65.6th percentile

Probability of exploitation in the next 30 days. Learn more

Weakness Enumeration

CWE-287

Affected Software

Vendor	Product	Versions
Dpgaspar	Flask-Appbuilder	< 3.3.4

References

https://github.com/dpgaspar/Flask-AppBuilder/commit/eba517aab121afa3f3f2edb011ec6bc4efd61fbcPatch, Third Party Advisory
https://github.com/dpgaspar/Flask-AppBuilder/releases/tag/v3.3.4Release Notes, Third Party Advisory
https://github.com/dpgaspar/Flask-AppBuilder/security/advisories/GHSA-m3rf-7m4w-r66qThird Party Advisory
https://github.com/dpgaspar/Flask-AppBuilder/commit/eba517aab121afa3f3f2edb011ec6bc4efd61fbcPatch, Third Party Advisory
https://github.com/dpgaspar/Flask-AppBuilder/releases/tag/v3.3.4Release Notes, Third Party Advisory
https://github.com/dpgaspar/Flask-AppBuilder/security/advisories/GHSA-m3rf-7m4w-r66qThird Party Advisory

Timeline

Published: Dec 9, 2021
Last Modified: Jun 17, 2026
Status: Modified

Frequently Asked Questions

What is CVE-2021-41265?

How severe is CVE-2021-41265?

CVE-2021-41265 has a CVSS score of 8.8/10 (HIGH severity). The EPSS model estimates a 1.25% probability of exploitation in the next 30 days.

How do I fix CVE-2021-41265?

Check the vendor references and advisories linked above for patched versions and mitigation guidance. You can also run a Strix scan to test if your systems are affected.

Are you affected by CVE-2021-41265?

Run a free Strix scan to check your systems for this vulnerability.

Scan your code now

Source: NVD / NIST