Fleet is open source device management software. In versions prior to 4.78.3, 4.77.1, 4.76.2, 4.75.2, and 4.53.3, a vulnerability in Fleet's Windows MDM enrollment flow could allow an attacker to submit forged authentication tokens that are not properly validated. Because JWT signatures were not verified, Fleet could accept attacker-controlled identity claims, enabling enrollment of unauthorized devices under arbitrary Azure AD user identities. Versions 4.78.3, 4.77.1, 4.76.2, 4.75.2, and 4.53.3 fix the issue. If an immediate upgrade is not possible, affected Fleet users should temporarily disable Windows MDM.
History

Fri, 23 Jan 2026 16:45:00 +0000

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

Thu, 22 Jan 2026 23:00:00 +0000

Type Values Removed Values Added
Metrics ssvc

{'options': {'Automatable': 'yes', 'Exploitation': 'none', 'Technical Impact': 'total'}, 'version': '2.0.3'}


Wed, 21 Jan 2026 22:00:00 +0000

Type Values Removed Values Added
Description Fleet is open source device management software. In versions prior to 4.78.3, 4.77.1, 4.76.2, 4.75.2, and 4.53.3, a vulnerability in Fleet's Windows MDM enrollment flow could allow an attacker to submit forged authentication tokens that are not properly validated. Because JWT signatures were not verified, Fleet could accept attacker-controlled identity claims, enabling enrollment of unauthorized devices under arbitrary Azure AD user identities. Versions 4.78.3, 4.77.1, 4.76.2, 4.75.2, and 4.53.3 fix the issue. If an immediate upgrade is not possible, affected Fleet users should temporarily disable Windows MDM.
Title Fleet has a JWT signature bypass vulnerability in Azure AD MDM enrollment
Weaknesses CWE-347
References
Metrics cvssV4_0

{'score': 9.3, 'vector': 'CVSS:4.0/AV:N/AC:L/AT:N/PR:N/UI:N/VC:H/VI:H/VA:H/SC:N/SI:N/SA:N'}


cve-icon MITRE

Status: PUBLISHED

Assigner: GitHub_M

Published: 2026-01-21T21:50:47.998Z

Updated: 2026-01-22T16:49:50.477Z

Reserved: 2026-01-13T18:22:43.980Z

Link: CVE-2026-23518

cve-icon Vulnrichment

Updated: 2026-01-22T15:13:37.869Z

cve-icon NVD

Status : Received

Published: 2026-01-21T22:15:50.140

Modified: 2026-01-21T22:15:50.140

Link: CVE-2026-23518

cve-icon Redhat

No data.