MEDIUM4.3

PYSEC-2026-1381

Flask-AppBuilder's OAuth login page subject to Cross Site Scripting (XSS)

Quick fix

PYSEC-2026-1381 — flask-appbuilder: upgrade to the fixed version with the command below.

pip install --upgrade 'flask-appbuilder>=4.2.1'

Details

### Impact A Cross-Site Scripting (XSS) vulnerability has been discovered on the OAuth login page. An attacker could trick a user to follow a specially crafted URL to the OAuth login page. This URL could inject and execute malicious javascript code that would get executed on the user's browser.

Impacted versions: Flask-AppBuilder version 4.1.4 up to and including 4.2.0

### Patches This issue was introduced on 4.1.4 and patched on 4.2.1, user's should upgrade to 4.2.1 or newer versions.

Are you affected?

Enter the version of the package you're using.

Affected packages

PyPI/flask-appbuilder

Introduced in: 4.1.4Fixed in: 4.2.1

Fixpip install --upgrade 'flask-appbuilder>=4.2.1'

References

https://github.com/dpgaspar/Flask-AppBuilder/security/advisories/GHSA-fqxj-46wg-9v84[WEB]
https://nvd.nist.gov/vuln/detail/CVE-2024-27083[ADVISORY]
https://github.com/dpgaspar/Flask-AppBuilder/commit/3d17741886e4b3c384d0570de69689e4117aa812[WEB]
https://github.com/dpgaspar/Flask-AppBuilder[PACKAGE]
https://pypi.org/project/flask-appbuilder[PACKAGE]
https://github.com/advisories/GHSA-fqxj-46wg-9v84[ADVISORY]