CVE-2021-3391
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 · uneditedMobileIron Mobile@Work through 2021-03-22 allows attackers to distinguish among valid, disabled, and nonexistent user accounts by observing the number of failed login attempts needed to produce a Lockout error message
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 confidenceMobileIron Mobile@Work has an account enumeration vulnerability where the system reveals different lockout timing behaviors for valid, disabled, and nonexistent user accounts. Attackers can distinguish account types by counting failed login attempts before receiving a Lockout error, enabling user enumeration for further 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<= 11.0.0.0.115r<= 12.11.1CVSS 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 MobileIron Mobile@Work deploymentInventory your mobile device management (MDM) or enterprise mobility management (EMM) systems to confirm MobileIron Mobile@Work is in use as a client application or component in your environment.Affected if MobileIron Mobile@Work is deployed in the environment
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Determine installed versionCheck the version of MobileIron Mobile@Work installed on managed devices or the MobileIron core/connector components. Compare against affected versions: 11.0.0.0.115r and below, or 12.11.1 and below.Affected if The installed version is 11.0.0.0.115r or lower, OR 12.11.1 or lower
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Observe login response timingAttempt a series of failed login attempts using different account types (a valid account, a disabled account, and a nonexistent account) and measure the time until each account type receives a Lockout error response.Affected if Different account types reach lockout after different numbers of failed attempts, indicating timing-based enumeration is possible
You are affected if MobileIron Mobile@Work is deployed at version 11.0.0.0.115r or lower, or version 12.11.1 or lower, and the login system exhibits differing lockout timing behaviors between valid, disabled, and nonexistent accounts.
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 failed login handling so all accounts (valid, disabled, nonexistent) trigger lockout after the same number of attempts, and normalize error responses to prevent timing-based enumeration.
- Consultation3.0 h
- Implementation6.0 h
- Testing4.0 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 $4,224.
Scan for this in your stack
Free · runs locallyCheck whether your project pulls in CVE-2021-3391 — 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-2021-3391 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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