CVE-2026-23518

Summary

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 Software

VendorProductVersion RangeStatus
fleetdmfleet>= 4.78.0, < 4.78.3affected
fleetdmfleet>= 4.77.0, < 4.77.1affected
fleetdmfleet>= 4.76.0, < 4.76.2affected
fleetdmfleet>= 4.75.0, < 4.75.2affected
fleetdmfleet< 4.53.3affected

Weaknesses

  • CWE-347: CWE-347: Improper Verification of Cryptographic Signature

ADP Enrichment

CISA ADP Vulnrichment

  • SSVC:
  • Exploitation: none
    • Automatable: yes
    • Technical Impact: total

References