CVE-2021-29621

Flask-AppBuilder is a development framework, built on top of Flask. User enumeration in database authentication in Flask-AppBuilder <= 3.2.3. Allows for a non authenticated user to enumerate existing accounts by timing the response time from the server when you are logging in. Upgrade to version 3.3.0 or higher to resolve.

• CWE-203
• CWE-203

• https://github.com/dpgaspar/Flask-AppBuilder/commit/780bd0e8fbf2d36ada52edb769477e0a4edae580Patch, Third Party Advisory
• https://github.com/dpgaspar/Flask-AppBuilder/security/advisories/GHSA-434h-p4gx-jm89Third Party Advisory
• https://lists.apache.org/thread.html/r466759f377651f0a690475d5a52564d0e786e82c08d5a5730a4f8352%40%3Cannounce.apache.org%3E
• https://lists.apache.org/thread.html/r5b754118ba4e996adf03863705d34168bffec202da5c6bdc9bf3add5%40%3Cannounce.apache.org%3E
• https://lists.apache.org/thread.html/r91067f953906d93aaa1c69fe2b5472754019cc6bd4f1ba81349d62a0%40%3Ccommits.airflow.apache.org%3E
• https://pypi.org/project/Flask-AppBuilder/Product, Third Party Advisory
• https://github.com/dpgaspar/Flask-AppBuilder/commit/780bd0e8fbf2d36ada52edb769477e0a4edae580Patch, Third Party Advisory
• https://github.com/dpgaspar/Flask-AppBuilder/security/advisories/GHSA-434h-p4gx-jm89Third Party Advisory
• https://lists.apache.org/thread.html/r466759f377651f0a690475d5a52564d0e786e82c08d5a5730a4f8352%40%3Cannounce.apache.org%3E
• https://lists.apache.org/thread.html/r5b754118ba4e996adf03863705d34168bffec202da5c6bdc9bf3add5%40%3Cannounce.apache.org%3E
• https://lists.apache.org/thread.html/r91067f953906d93aaa1c69fe2b5472754019cc6bd4f1ba81349d62a0%40%3Ccommits.airflow.apache.org%3E
• https://pypi.org/project/Flask-AppBuilder/Product, Third Party Advisory

Published

Jun 7, 2021

Last Modified

Jun 17, 2026

Status

Modified

• How Strix found a critical auth bypass in etcdStrix autonomously discovered a critical authentication bypass in etcd, later designated CVE-2026-33413.
• Autonomous PentestingAI agents that find and validate exploitable vulnerabilities like this one across your applications.
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