CVE-2025-24023
Official description Straight from the sourceThe vendor's or NVD's own wording, published unedited. Authoritative, but often terse — it says what broke, rarely what to do.
NVD · uneditedFlask-AppBuilder is an application development framework. Prior to 4.5.3, Flask-AppBuilder allows unauthenticated users to enumerate existing usernames by timing the response time from the server when brute forcing requests to login. This vulnerability is fixed in 4.5.3.
Technical summary Written by usOur analysis, written from the advisory, the CVSS vector and the affected-version data. It adds context the advisory leaves out, and never invents facts that are not in the source.
dbcve analysis · high confidenceFlask-AppBuilder prior to 4.5.3 contains a timing-based username enumeration vulnerability in its login endpoint. Unauthenticated attackers can determine whether specific usernames exist in the system by measuring subtle differences in server response times when submitting login requests with various usernames. This information leak allows adversaries to build a list of valid usernames for subsequent attacks.
Verify against the referenced sources before acting — the references below are authoritative for this CVE, this summary is not.
Affected products & versions What the vendor confirmedThe version ranges the vendor confirmed as vulnerable. If your version sits inside a range here, treat yourself as exposed until you have upgraded.
NVD · CPE data< 4.5.3CVSS breakdown How the score is builtThe industry scoring standard. It rates how the flaw is reached, what it takes to exploit, and what an attacker gains — the score is derived from those, not the other way round.
From the vector- Attack vector
- Network
- Complexity
- Low
- Privileges
- None
- User interaction
- None
- Scope
- Unchanged
- Confidentiality
- Low
- Integrity
- None
- Availability
- None
CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:L/I:N/A:N
Am I affected? How to checkSteps we derive from the advisory and the affected-version data, so you can decide whether this CVE reaches your setup. They are a guide, not a scan — your own configuration is the authority.
dbcve checksWork through these to decide whether this CVE applies to you.
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Identify Flask-AppBuilder installation and versionRun 'pip show flask-appbuilder' or check your requirements.txt/environment for the installed version of Flask-AppBuilderAffected if The installed version is lower than 4.5.3 (e.g., 4.5.2, 4.5.1, 4.4.x, etc.)
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Confirm the application uses the built-in login endpointInspect your Flask-AppBuilder application code to verify the default login view (typically at /login or /auth/login) is enabled and accessibleAffected if The application exposes a Flask-AppBuilder login endpoint without constant-time comparison protections
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Verify unauthenticated access to login functionalityAttempt to access the login page without authentication - confirm the endpoint responds to unauthenticated requestsAffected if The login endpoint accepts unauthenticated requests (no authentication required to trigger the timing difference)
You are affected if Flask-AppBuilder version is below 4.5.3 and your login endpoint is accessible to unauthenticated users, allowing attackers to measure timing differences between valid and invalid usernames.
Generated from the published advisory. Verify against your own configuration.
Remediation Closing itWhat it takes to close this. Where a vendor fix exists we point at it; where none exists we say so plainly, and can build one. Effort estimates are scoped from the advisory, not from your codebase.
dbcve · scoped4.5.3
Upgrade Flask-AppBuilder to version 4.5.3 or later to obtain the upstream fix. If immediate upgrading is not feasible, implement rate limiting, account lockout policies, and constant-time comparison logic on the login endpoint to mitigate timing differences.
4.5.3
- Check current installed version: pip show flask-appbuilder
- Upgrade Flask-AppBuilder to version 4.5.3 or later: pip install --upgrade flask-appbuilder>=4.5.3
- Verify the upgrade was successful: pip show flask-appbuilder
Generated from the published advisory — verify against the referenced sources before acting.
- Consultation1.0 h
- Implementation2.0 h
- Testing2.0 h
- Review / QA1.0 h
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Scan for this in your stack
Free · runs locallyCheck whether your project pulls in CVE-2025-24023 — or any other known-vulnerable package — straight from your lock files. Free and open source; it runs locally and uploads nothing.
References Go to the primary sourcePrimary sources — vendor advisories, patches and trackers. Where our summary and a reference disagree, the reference wins.
Primary sourcesPractitioner notes
ContributedPeer-ranked notes from engineers who’ve handled CVE-2025-24023 in production — separate from our analysis above.
The advisory tells you what broke. It rarely tells you what actually worked. If you’ve dealt with this one, that detail is what the next engineer is searching for.
- The version that genuinely resolved it — not the one the vendor claimed
- A config change or rule that shut the vector down
- A gotcha in the upgrade path that cost you an afternoon
No notes yet
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- Version or environment caveats, and links to real fixes
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