CVE-2021-41265 json
Improper Authentication in Flask-AppBuilder
published 2021-12-09 4 y ago modified 2026-07-08 4 mo ago also GHSA-m3rf-7m4w-r66q , PYSEC-2021-851 , EUVD-2021-0082
- cvss
- 8.1
- version 3.1, CNA
- cisa kev
- Not listed
- not in CISA's catalog
- epss
- 1.3%
- EPSS 1.3% chance of exploitation in 30 days, percentile 70%
- public exploits
- 0
- none known
Summary
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.
Patch / fix
- pypi flask-appbuilder 3.3.4
- dpgaspar flask-appbuilder 3.3.4
Exploit prediction
1.32% chance of exploitation in the next 30 days, higher than 70% of all scored CVEs (FIRST EPSS, 2026-11-08).
CVSS scores
| assigned by | version | score | vector |
|---|---|---|---|
| CNA | 3.1 | 8.1 | CVSS:3.1/AV:N/AC:L/PR:L/UI:N/S:U/C:H/I:H/A:N |
| NVD | 3.1 | 8.8 | CVSS:3.1/AV:N/AC:L/PR:L/UI:N/S:U/C:H/I:H/A:H |
| NVD | 2.0 | 6.5 | AV:N/AC:L/Au:S/C:P/I:P/A:P |
| GitHub | 3.1 | 8.1 | CVSS:3.1/AV:N/AC:L/PR:L/UI:N/S:U/C:H/I:H/A:N |
Affected packages
| ecosystem | package | affected | fixed in |
|---|---|---|---|
| pypi | flask-appbuilder | <3.3.4 |
3.3.4 |
Affected products
- dpgaspar Flask-AppBuilder
Classification
- Weakness
-
- CWE-287 Improper Authentication
References
-
github.com
/dpgaspar/Flask-AppBuilder/commit/eba517aab121afa3f3f2edb011ec6bc4efd61fbc
web, patch, third-party-advisory
-
github.com
/dpgaspar/Flask-AppBuilder/security/advisories/GHSA-m3rf-7m4w-r66q
web, third-party-advisory, advisory
-
github.com
/dpgaspar/Flask-AppBuilder/releases/tag/v3.3.4
web, release-notes, third-party-advisory
-
nvd.nist.gov
/vuln/detail/CVE-2021-41265
advisory
-
github.com
/dpgaspar/Flask-AppBuilder
package
-
github.com
/pypa/advisory-database/tree/main/vulns/flask-appbuilder/PYSEC-2021-851.yaml
web
Sources
- CVE List CVE-2021-41265
- GitHub Advisory GHSA-m3rf-7m4w-r66q
- NVD CVE-2021-41265
- OSV PYSEC-2021-851
Fencer Vulns keeps one entry per vulnerability: the CVE id wins, then GHSA, and records that alias each other are merged, except that two CVEs always keep separate entries. The same data is available as JSON.