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FleetApplication · Fleetdm

CVE-2026-34391

HIGH · 7.5 CVSS v3.1 Published 2026-03-27
Fix available
A fix is available. Upgrade to 4.81.1 or later.
See remediation →
84/100
Remediation priority · High
Remotely reachable No privileges Zero-click

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 · unedited
Fleet is open source device management software. Prior to 4.81.1, a vulnerability in Fleet's Windows MDM command processing allows a malicious enrolled device to access MDM commands intended for other devices, potentially exposing sensitive configuration data such as WiFi credentials, VPN secrets, and certificate payloads across the entire Windows fleet. Version 4.81.1 patches the issue.

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 confidence

A vulnerability in Fleet's Windows MDM command processing allows a malicious enrolled device to bypass access controls and retrieve MDM commands intended for other devices. This cross-device command access exposes sensitive configuration payloads including WiFi credentials, VPN secrets, and certificates across the Windows fleet.

MitigationUpgrade Fleet to version 4.81.1 or later. Review MDM command logs for signs of unauthorized cross-device command retrieval and consider rotating any credentials that may have been exposed.

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
FleetApplication
Affected:< 4.81.1

CVSS 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 checks

Work through these to decide whether this CVE applies to you.

  1. Check installed Fleet version
    Run `fleetctl version` from the Fleet management host or access the Fleet UI and navigate to the version information typically found in the settings or about section
    Affected if The displayed version number is less than 4.81.1
  2. Confirm Windows MDM enrollment is active
    Access the Fleet UI and check if any Windows devices are enrolled in MDM, or query the Fleet database for devices with MDM profiles applied to Windows hosts
    Affected if Windows MDM enrollment exists and the Fleet version is below 4.81.1
  3. Inspect MDM command logs for unauthorized access patterns
    Review Fleet's MDM command audit logs or database records of command deliveries, looking for entries where a device retrieved commands assigned to a different device identifier
    Affected if Logs show any Windows device accessing MDM commands destined for other devices

If Fleet version is below 4.81.1 and Windows MDM enrollment is configured, the environment contains the vulnerable code path.

Generated from the published advisory. Verify against your own configuration.

Check your environment

Paste your version and any relevant configuration and it will be compared against the affected criteria above. Do not include secrets or credentials.

AI-assisted, checked against the advisory. Informational, not a guarantee.

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 · scoped
Upgrade available Upgrade to 4.81.1 or later
Fixed in 4.81.1
Interim mitigation

Upgrade Fleet to version 4.81.1 or later. Review MDM command logs for signs of unauthorized cross-device command retrieval and consider rotating any credentials that may have been exposed.

Recommended fix High confidence

4.81.1

  1. Verify current Fleet version by checking the running container or deployment
  2. Review Fleet upgrade documentation for your deployment method (Docker, Kubernetes, etc.)
  3. Create a backup of the Fleet database and configuration files
  4. Pull the Fleet 4.81.1 container image or obtain the 4.81.1 release package
  5. Stop the currently running Fleet instance
  6. Apply the upgrade following Fleet's standard upgrade procedure for your deployment
  7. Verify the upgrade was successful by checking the Fleet version
  8. Test MDM functionality to ensure Windows MDM command processing is working correctly

Generated from the published advisory — verify against the referenced sources before acting.

Fix this in Fleet Scoped from the published advisory
  • Consultation4.0 h
  • Implementation4.0 h
  • Testing6.0 h
  • Review / QA3.0 h
17.0 hours of engineering $2,960
Get the upgrade done

An estimate, not a bill — we confirm scope with you before any work starts. Need it this week? Rush from $4,736.

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References Go to the primary sourcePrimary sources — vendor advisories, patches and trackers. Where our summary and a reference disagree, the reference wins.

Primary sources

Practitioner notes

Contributed

Peer-ranked notes from engineers who’ve handled CVE-2026-34391 in production — separate from our analysis above.

No notes yet

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What this is

A place for practitioners to share what actually worked: a mitigation you’ve tested, a configuration change, a version- or environment-specific caveat, or a link to a verified patch. The most useful notes rise to the top as peers upvote them, so the signal stays high.

What belongs here
  • 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
  • No spam, self-promotion, credentials, or personal data