How severe is CVE-2021-32805?

CVE-2021-32805 has a CVSS score of 6.1/10, rated MEDIUM. Review your exposure and patch according to your risk tolerance.

Which packages are affected by CVE-2021-32805?

CVE-2021-32805 affects the following packages: flask-appbuilder (PyPI). Ecosystems affected: PyPI.

How do I fix CVE-2021-32805?

Update flask-appbuilder to 3.3.2 or later, then make sure no transitive (indirect) dependency still pins the vulnerable range — O3 confirms CVE-2021-32805 is resolved across your whole dependency graph.

How do I detect CVE-2021-32805 in my PyPI dependencies?

Scan your dependency tree (package-lock.json, pnpm-lock.yaml, requirements.txt, go.sum, etc.) for flask-appbuilder. O3's reachability analysis confirms whether the vulnerable code path is actually invoked in your application, so you act on real exposure instead of every transitive match.

How do I mitigate CVE-2021-32805 if there is no patch (or I can't update yet)?

If you can't upgrade right away: gate or disable the affected feature, validate untrusted input at the boundary, and avoid passing attacker-controlled data into the vulnerable path. O3's runtime protection blocks exploitation in production as an interim safeguard until the upgrade lands.

How does O3 Security protect against CVE-2021-32805?

O3 pinpoints whether CVE-2021-32805 is reachable in your code and exactly where to fix it, then blocks exploitation in production at runtime until the patched version is deployed.

Is CVE-2021-32805 actively exploited in the wild?

No public exploit code has been indexed for CVE-2021-32805 yet. This does not mean the vulnerability cannot be exploited — absence of public exploits does not imply safety. Apply the recommended fix and use O3 Security to monitor your exposure.

What is the EPSS score for CVE-2021-32805?

CVE-2021-32805 has an EPSS (Exploit Prediction Scoring System) score of 0.7%, placing it in the 48th percentile of all CVEs. EPSS is maintained by FIRST.org and estimates the probability that a vulnerability will be exploited in the wild within the next 30 days. This score indicates relatively lower exploitation probability, though the CVSS severity should still guide your patching priority.

What type of vulnerability is CVE-2021-32805?

CVE-2021-32805 is classified as Open Redirect (CWE-601). This weakness type describe the underlying flaw category, which helps determine the potential impact and the right class of mitigation.

When was CVE-2021-32805 published, and has it been updated?

CVE-2021-32805 was published on September 8, 2021 and was last updated on March 13, 2026. Advisory data evolves as severity scores, affected ranges, and exploit intelligence are revised — always check the latest version of the advisory before acting.

🐍 PyPI

CVE-2021-32805

MEDIUM

Flask-AppBuilder Open Redirect vulnerability

Also known asGHSA-624f-cqvr-3qw4PYSEC-2021-359

Published

Sep 8, 2021

Updated

Mar 13, 2026

Affected

1 pkg

Patched

1 / 1

Exploits

None indexed

EPSS Exploitation Probability

via FIRST.org ↗

0.7%probability of exploitation in next 30 days

Lower Risk48th percentile+0.49%

EPSS (Exploit Prediction Scoring System) is a daily probability model maintained by FIRST.org. It estimates the likelihood a CVE will be exploited in production environments within the next 30 days, derived from real-world threat intelligence signals.

Blast Radius

1 pkg affected

🐍flask-appbuilder

Real-time download stats are indexed for npm and PyPI packages. This vulnerability affects PyPI packages — download data is not available via public APIs for these ecosystems.

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.

Affected Packages

1 total 1 fixed

Ecosystem	Package	Vulnerable range	Fix
🐍PyPI	`flask-appbuilder`	all versions	3.3.2

Detection & mitigation playbook

Open-source dependency

Detect
Scan your dependency tree (package-lock.json, pnpm-lock.yaml, requirements.txt, go.sum, etc.) for flask-appbuilder. O3's reachability analysis confirms whether the vulnerable code path is actually invoked in your application, so you act on real exposure instead of every transitive match.
Fix
Update flask-appbuilder to 3.3.2 or later, then make sure no transitive (indirect) dependency still pins the vulnerable range — O3 confirms CVE-2021-32805 is resolved across your whole dependency graph.
Workarounds
If you can't upgrade right away: gate or disable the affected feature, validate untrusted input at the boundary, and avoid passing attacker-controlled data into the vulnerable path. O3's runtime protection blocks exploitation in production as an interim safeguard until the upgrade lands.
How O3 protects you
O3 pinpoints whether CVE-2021-32805 is reachable in your code and exactly where to fix it, then blocks exploitation in production at runtime until the patched version is deployed.

Tailored to CVE-2021-32805. Runtime protection reduces exposure until a permanent patch is applied and verified — it complements patching, it doesn't replace it.

Frequently Asked Questions

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.

O3 Security · Impact-Aware SCA

Is CVE-2021-32805 in your dependencies?

O3 detects CVE-2021-32805 across PyPI dependencies and uses function-level reachability to confirm whether the vulnerable code path is actually reachable — not just present. No false positives.

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