CVE-2021-34580
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 · uneditedIn mymbCONNECT24, mbCONNECT24 <= 2.9.0 an unauthenticated user can enumerate valid backend users by checking what kind of response the server sends for crafted invalid login attempts.
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 confidenceIn mymbCONNECT24 and mbCONNECT24 versions 2.9.0 and prior, an unauthenticated attacker can enumerate valid backend user accounts by submitting login requests and analyzing the differential server responses for valid versus invalid usernames, allowing discovery of valid account identifiers.
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<= 2.9.0<= 2.9.0CVSS 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
- High
- Integrity
- None
- Availability
- None
CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:H/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 installed mbCONNECT24 versionCheck the application version in the product UI, configuration files, or about page. Compare against the affected range: versions 2.9.0 and prior.Affected if Installed version is 2.9.0 or lower
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Verify login endpoint is externally accessibleDetermine if the login page (typically at /login or the root path of the web interface) is reachable without authentication from the network.Affected if Login page is accessible to unauthenticated users
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Test for username enumeration in login responsesSubmit two login attempts with different usernames (one likely valid, one random) using the same incorrect password. Compare the HTTP status codes, error messages, and response times between the two requests.Affected if The server returns different error messages, different HTTP status codes, or measurably different response times for valid usernames versus invalid usernames
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Check for rate limiting or account lockoutSubmit multiple failed login attempts with different usernames in rapid succession. Observe if the application blocks, throttles, or locks accounts after a certain number of attempts.Affected if No rate limiting or account lockout is enforced, allowing unlimited login attempts
The environment is affected if mbCONNECT24 or mymbCONNECT24 version 2.9.0 or lower is installed and the login page is accessible without authentication, with the server returning distinguishable responses that reveal valid 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.
From vendor dataImplement uniform generic error messages for failed login attempts regardless of username validity, combined with rate limiting and account lockout policies to prevent automated enumeration attacks.
- Consultation2.0 h
- Implementation4.0 h
- Testing3.0 h
- Review / QA2.0 h
An estimate, not a bill — we confirm scope with you before any work starts. Need it this week? Rush from $3,088.
Scan for this in your stack
Free · runs locallyCheck whether your project pulls in CVE-2021-34580 — 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-2021-34580 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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- Verified mitigations, workarounds, and config changes
- Version or environment caveats, and links to real fixes
- No weaponised exploit code, or anything meant to cause harm
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