CVE-2026-23518: critical vulnerability in fleetdm fleet
Fleet has a JWT signature bypass vulnerability in Azure AD MDM enrollment
Published · Updated
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28Vexday Risk Score
No sign of exploitation. No public exploitation artifact known so far.
ssvc Trackcvss 9.3epss 0.3%
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.
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
Affected products
fleetdm · fleetRelated CVEs — fleetdm fleet
In the same product, most dangerous first.
CVE-2020-26276CRITICALSAML authentication vulnerability in FleetEPSS 2.2%CVE-2021-21296LOWDenial-of-service in FleetEPSS 2.0%CVE-2026-34387MEDIUMFleet vulnerable to OS command injection via crafted software package metadata in uninstall scriptsEPSS 1.3%CVE-2022-23600MEDIUMLimited ability to spoof SAML authentication with missing audience verificationEPSS 0.9%CVE-2022-24841MEDIUMImproper Authorization in github.com/fleetdm/fleetEPSS 0.8%CVE-2026-26191MEDIUMFleet vulnerable to OS command injection in software packagesEPSS 0.8%