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© 2026 FAUCET Technologies LLC. All rights reserved.

CVE-2026-23998

28
FAUCET Score

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.

First published: May 14, 2026Last modified: May 14, 2026

Impacted Technologies

VendorProductVersion(s)CPE
< 4.81.0CPE matchmatch criteria
cpe:2.3:a:fleetdm:fleet:*:*:*:*:*:*:*:*

CVSS Data

CVSS version used by this source: 4.0

8.2HIGH

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/E:X/CR:X/IR:X/AR:X/MAV:X/MAC:X/MAT:X/MPR:X/MUI:X/MVC:X/MVI:X/MVA:X/MSC:X/MSI:X/MSA:X/S:X/AU:X/R:X/V:X/RE:X/U:X

Attack Vector
NETWORK
Attack Complexity
HIGH
Attack Requirements
NONE
Privileges Required
NONE
User Interaction
NONE
VS Confidentiality
HIGH
VS Integrity
NONE
VS Availability
NONE
SS Confidentiality
NONE
SS Integrity
NONE
SS Availability
NONE
Exploit Maturity
NOT_DEFINED
CvssVersion
4.0

Exploit Intelligence

EPSS Score
0.21%
Probability of exploitation in next 30 days
EPSS Percentile
12.0%
Percentile rank of EPSS score among Peer Group
As of 2026-07-27
Model: v2026.06.15
This CVE's current EPSS score of 0.0021 is in the 1st percentile among its peer group of 51,551 CVEs.

Social Chatter

The average CVE in this peer group has 0.0 Twitter, 0.0 Reddit, 0.1 Bluesky, 0.1 Mastodon, and 0.4 GitHub mentions.

Media Mentions

No media coverage found for this CVE.

The average CVE in this peer group has 0.1 InfoSec Media, 0.0 Vendor Blog, and 0.0 Security Researcher mentions.

Remediation

Patch Available

Vendor Patches (2)

gopatch availablevia ghsa
Product: github.com/fleetdm/fleet/v4Fixed in: 4.81.0
github_advisoryworkaround availablevia nvd_reference
View patch

Vendor Advisories (1)

goGHSA-2rc4-7jc6-qffhhigh

Fleet has a Windows MDM management endpoint authentication bypass

May 14, 2026

References

github.com / fleetdm/fleet/releases/tag/fleet-v4.81.0
ProductRelease Notes
github.com / fleetdm/fleet/security/advisories/GHSA-2rc4-7jc6-qffh
MitigationVendor Advisory