# CVE-2021-32805: URL Redirection to Untrusted Site ('Open Redirect') in Flask-AppBuilder

> An attacker can craft URLs to redirect users to malicious sites in Flask-AppBuilder applications using OAuth, requiring an upgrade to fix.

- **Severity:** High 7.2 (`CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:C/C:L/I:L/A:N`)
- **Exploited in the wild:** Not known
- **Login needed:** Not needed
- **Attackable:** Over the internet
- **Victim action needed:** Not needed
- **Fix available:** Yes
- **Published:** 8 Sep 2021
- **Updated:** 3 Aug 2024
- **Also known as:** GHSA-624f-cqvr-3qw4, PYSEC-2021-359

## What is CVE-2021-32805?

CVE-2021-32805 is a high-severity vulnerability in dpgaspar Flask-AppBuilder, published on 8 Sep 2021. An attacker can exploit it over the internet without logging in, with no action from the victim.

### Official description

Flask-AppBuilder is an application development framework, built on top of Flask. In affected versions if using Flask-AppBuilder OAuth, an attacker can share a carefully crafted URL with a trusted domain for an application built with Flask-AppBuilder, this URL can redirect a user to a malicious site. This is an open redirect vulnerability. To resolve this issue upgrade to Flask-AppBuilder 3.2.2 or above. If upgrading is infeasible users may filter HTTP traffic containing `?next={next-site}` where the `next-site` domain is different from the application you are protecting as a workaround.

Weakness: CWE-601 (URL Redirection to Untrusted Site)

## Which versions are affected by CVE-2021-32805?

3 open source packages ship an affected version, including flask-appbuilder and Flask-AppBuilder. It affects 1 product.


| Package | Ecosystem | Affected | Fixed in |
| --- | --- | --- | --- |
| `flask-appbuilder` | PyPI | All versions | 3.3.2 |
| `flask-appbuilder` | PyPI | All versions | 3.3.2 |
| `Flask-AppBuilder` | PyPI | All versions | 3.3.2 |

Products: Dpgaspar Flask-Appbuilder.

## How do I fix CVE-2021-32805?

Upgrade flask-appbuilder to 3.3.2 or later.

## Is CVE-2021-32805 being exploited?

There is no known exploitation of CVE-2021-32805 in the wild and no public exploit code.

## Other vulnerabilities in dpgaspar Flask-AppBuilder

- [CVE-2024-25128](https://insights.sbomify.com/CVE-2024-25128/): Flask-AppBuilder incorrect authentication when using auth type OpenID (critical 9.1)
- [CVE-2021-41265](https://insights.sbomify.com/CVE-2021-41265/): Improper Authentication in Flask-AppBuilder (high 8.1)
- [CVE-2023-29005](https://insights.sbomify.com/CVE-2023-29005/): No Rate Limiting on Login AUTH DB (high 7.5)
- [CVE-2025-58065](https://insights.sbomify.com/CVE-2025-58065/): Flask App Builder has an Authentication Bypass vulnerability when using non AUTH_DB methods (medium 6.5)
- [CVE-2022-24776](https://insights.sbomify.com/CVE-2022-24776/): Open Redirect in Flask-AppBuilder (medium 6.1)

## Fix prompt for AI coding agents

```text
Check this codebase for CVE-2021-32805 and fix it if it is affected.

What it is: CVE-2021-32805 is a high-severity vulnerability in dpgaspar Flask-AppBuilder, published on 8 Sep 2021. An attacker can exploit it over the internet without logging in, with no action from the victim.
Exploitation: There is no known exploitation of CVE-2021-32805 in the wild and no public exploit code.

Affected packages and fixed versions:
- flask-appbuilder (PyPI): affected all versions; fixed in 3.3.2
- flask-appbuilder (PyPI): affected all versions; fixed in 3.3.2
- Flask-AppBuilder (PyPI): affected all versions; fixed in 3.3.2

Task:
1. Search the dependency manifests and lockfiles (for example package.json, package-lock.json, requirements.txt, poetry.lock, uv.lock, pom.xml, build.gradle, go.mod, Cargo.lock, Gemfile.lock) and any Dockerfiles for the affected packages, including transitive dependencies.
2. If an affected version is in use, upgrade it to the fixed version for its release line with the project's package manager, so the lockfile is regenerated. Prefer the smallest upgrade that fixes it.
3. If there is no fix, or the upgrade would break the build, do not guess: explain the risk and the safest workaround instead.
4. Run the tests and summarise what changed and why.
5. If nothing in the project is affected, say so and change nothing.

Reference: https://insights.sbomify.com/CVE-2021-32805/ (Markdown: https://insights.sbomify.com/CVE-2021-32805/index.md)
```

## Sources

- CVE record: https://www.cve.org/CVERecord?id=CVE-2021-32805
- NVD: https://nvd.nist.gov/vuln/detail/CVE-2021-32805
- OSV: https://osv.dev/vulnerability/CVE-2021-32805

---
From sbomify Insights: https://insights.sbomify.com/CVE-2021-32805/
Summaries are generated and may contain mistakes; the official description above is the record.