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

Exploitation

No confirmed exploitation recorded. Patch Next marks exploitation only from CISA KEV.

CVSS

4.3 · CVSS:3.1/AV:N/AC:L/PR:N/UI:R/S:U/C:L/I:N/A:N

EPSS

• CVE-2024-27083: 0.57% estimated exploitation activity in the next 30 days; percentile 47.09 (FIRST EPSS, 2026-11-03). This is a model estimate, not proof of exploitation or customer exposure.

As published by the source; long descriptions are shortened.

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.

Published by the source

28 Feb 2024, 18:37 UTC

Last modified by the source

10 Sep 2026, 03:50 UTC

Source last checked

26 Oct 2026, 13:37 UTC

1. Revision 2 · amended · 26 Oct 2026

   Amended from ghsa record GHSA-fqxj-46wg-9v84

2. Revision 1 · created · 24 Oct 2026

   Published from osv record GHSA-fqxj-46wg-9v84

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# Patch Next advisory brief: CVE-2024-27083

Advisory: Flask-AppBuilder's OAuth login page subject to Cross Site Scripting (XSS)
IDs: CVE-2024-27083, GHSA-fqxj-46wg-9v84
Record: https://patchnext.com/advisories/cve-2024-27083 (revision 2, source checked 26 Oct 2026, 13:37 UTC)
Inventory: none attached. This brief comes from a public page and does not say whether any deployment is affected.
Severity: Medium (CVSS 4.3)
Exploitation: no confirmed exploitation recorded. Patch Next confirms exploitation only from CISA KEV.
Vendor response: Vendor fix available; fixed versions by package: flask-appbuilder 4.2.1. A vendor fix does not mean a deployment is fixed.

## Affected components
- PyPI flask-appbuilder: affected >= 4.1.4, < 4.2.1; fixed in 4.2.1

## Suggested inspection (read-only)
- `python -m pip show flask-appbuilder`: prints the installed version. Run with the environment that serves production active.

## Supported action
Upgrade each affected component to a fixed version on its release line. For a transitive dependency, upgrade the parent package or add an override or constraint, then regenerate the lockfile. Redeploy every environment that ran an affected version.

## Required regression checks
- Run the test suite and a production build.
- Exercise the features that depend on flask-appbuilder.
- Repeat the inspection and confirm that only fixed versions remain installed.

## Rollback considerations
- Keep the previous lockfile and deployment artifact. Rolling back reinstates the vulnerable version, so apply any documented mitigation while you fix forward.

## Unresolved questions
- Which deployments run an affected version?
- Exploitation status can change. Check again before lowering the priority.
- Mark the work resolved only after the fixed version is verified in production.

## Sources
- Verified: https://osv.dev/vulnerability/GHSA-fqxj-46wg-9v84 (OSV record GHSA-fqxj-46wg-9v84 lists affected ranges: PyPI flask-appbuilder >=4.1.4 <4.2.1 (fixed))
- Verified: https://github.com/advisories/GHSA-fqxj-46wg-9v84 (GitHub-reviewed advisory GHSA-fqxj-46wg-9v84 lists affected ranges: PyPI flask-appbuilder >=4.1.4 <4.2.1)

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