CVE-2026-24899: Fleet Windows MDM Azure AD JWT Authentication Bypass

May 14, 2026

A vulnerability in Fleet’s Windows MDM enrollment flow allows authentication tokens from any Azure AD tenant to be accepted. Because Fleet validates JWT signatures using Microsoft’s multi-tenant JWKS endpoint but does not enforce the aud (audience) or iss (issuer) claims, any Microsoft-signed Azure AD access token containing the expected scopes can be used to authenticate to Fleet’s MDM endpoints.

References

github.com/advisories/GHSA-ffg9-j72f-j6xm
github.com/fleetdm/fleet/releases/tag/fleet-v4.82.0
github.com/fleetdm/fleet/security/advisories/GHSA-ffg9-j72f-j6xm
nvd.nist.gov/vuln/detail/CVE-2026-24899

Code Behaviors & Features

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