Fleet is open source device management software. Prior to version 4.81.0, a vulnerability in Fleet’s Windows MDM management endpoint could allow requests to be processed without proper client certificate validation. In certain circumstances, this could allow an attacker to impersonate an enrolled Windows device and retrieve sensitive configuration data. Fleet’s Windows MDM management endpoint relies on mutual TLS (mTLS) client certificates to authenticate enrolled devices. In affected versions, requests that did not present a client certificate could be incorrectly treated as trusted. As a result, an attacker with prior knowledge of a valid enrolled device identifier could potentially impersonate that device and receive configuration payloads intended for it. These payloads may contain sensitive information such as Wi-Fi or VPN configuration data, certificates, or other secrets delivered through MDM profiles. This issue does not allow enrollment of new devices, administrative access to Fleet, or compromise of the Fleet control plane. Impact is limited to the targeted Windows device. Version 4.81.0 contains a patch. If an immediate upgrade is not possible, affected Fleet users should temporarily disable Windows MDM.

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Advisories
Source ID Title
Github GHSA Github GHSA GHSA-2rc4-7jc6-qffh Fleet has a Windows MDM management endpoint authentication bypass
Fixes

Solution

No solution given by the vendor.


Workaround

No workaround given by the vendor.

History

Thu, 14 May 2026 20:45:00 +0000

Type Values Removed Values Added
First Time appeared Fleetdm
Fleetdm fleet
Vendors & Products Fleetdm
Fleetdm fleet

Thu, 14 May 2026 19:00:00 +0000

Type Values Removed Values Added
Description Fleet is open source device management software. Prior to version 4.81.0, a vulnerability in Fleet’s Windows MDM management endpoint could allow requests to be processed without proper client certificate validation. In certain circumstances, this could allow an attacker to impersonate an enrolled Windows device and retrieve sensitive configuration data. Fleet’s Windows MDM management endpoint relies on mutual TLS (mTLS) client certificates to authenticate enrolled devices. In affected versions, requests that did not present a client certificate could be incorrectly treated as trusted. As a result, an attacker with prior knowledge of a valid enrolled device identifier could potentially impersonate that device and receive configuration payloads intended for it. These payloads may contain sensitive information such as Wi-Fi or VPN configuration data, certificates, or other secrets delivered through MDM profiles. This issue does not allow enrollment of new devices, administrative access to Fleet, or compromise of the Fleet control plane. Impact is limited to the targeted Windows device. Version 4.81.0 contains a patch. If an immediate upgrade is not possible, affected Fleet users should temporarily disable Windows MDM.
Title Fleet has a Windows MDM management endpoint authentication bypass
Weaknesses CWE-295
References
Metrics cvssV4_0

{'score': 8.2, 'vector': 'CVSS:4.0/AV:N/AC:H/AT:N/PR:N/UI:N/VC:H/VI:N/VA:N/SC:N/SI:N/SA:N'}


Projects

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cve-icon MITRE

Status: PUBLISHED

Assigner: GitHub_M

Published:

Updated: 2026-05-14T18:48:38.765Z

Reserved: 2026-01-19T18:49:20.658Z

Link: CVE-2026-23998

cve-icon Vulnrichment

No data.

cve-icon NVD

Status : Received

Published: 2026-05-14T19:16:30.983

Modified: 2026-05-14T19:16:30.983

Link: CVE-2026-23998

cve-icon Redhat

No data.

cve-icon OpenCVE Enrichment

Updated: 2026-05-14T20:30:04Z

Weaknesses