by Kastro CVE-2026-23518
fleetdm fleet — Fleet has a JWT signature bypass vulnerability in Azure AD MDM enrollment
Description · from the CVE record
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.
Affected
ProductAffectedFixed inSource
fleet>= 4.78.0, < 4.78.3–CNA
fleet>= 4.77.0, < 4.77.1–CNA
fleet>= 4.76.0, < 4.76.2–CNA
fleet>= 4.75.0, < 4.75.2–CNA
fleet< 4.53.3–CNA
Scores by source
NVD9.8CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:H/I:H/A:H
GitHub_M (CNA)9.3CVSS:4.0/AV:N/AC:L/AT:N/PR:N/UI:N/VC:H/VI:H/VA:H/SC:N/SI:N/SA:N
CISA ADPSSVCExploitation: none · Automatable: yes · Technical impact: total