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Windows MDM cross-device command disclosure

High
lukeheath published GHSA-wg7j-pcc3-h4rh Mar 27, 2026

Package

gomod github.com/fleetdm/fleet (Go)

Affected versions

< 4.81.1

Patched versions

>= 4.81.1

Description

Summary

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.

Impact

When a Windows device reports a specific SyncML status code during MDM communication, Fleet attempts to resend the original command by looking it up in a shared command table. A device-controlled value used in this lookup is not properly validated or scoped, allowing a malicious device to match commands belonging to other enrolled devices. Matched commands are then re-queued to the attacker's device and delivered on the next check-in.

Exploitation requires a device enrolled in Fleet's Windows MDM.

This issue does not affect instances where Windows MDM is disabled or environments with no enrolled Windows devices.

Workarounds

If an immediate upgrade is not possible, affected Fleet users should temporarily disable Windows MDM.

For more information

If you have any questions or comments about this advisory:

Email us at security@fleetdm.com
Join #fleet in osquery Slack

Credits

We thank @fuzzztf for responsibly reporting this issue.

Severity

High

CVE ID

CVE-2026-34391

Weaknesses

No CWEs

Credits