CVE-2026-24899: fleetdm fleet Authentication Bypass by Spoofing

Vulnerability summary

CVE-2026-24899 is a high (CVSS 8.2) Authentication Bypass by Spoofing vulnerability in fleetdm fleet. EPSS estimates a 0.38% chance of exploitation in the next 30 days, higher than 30.6% of scored vulnerabilities.

Timeline

1. 14-05-2026
   PublishedVulnerability first disclosed.
2. 16-05-2026
   Last modifiedVulnerability information updated.

Description

Fleet is open source device management software. Prior to version 4.82.0, 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. If Windows MDM is enabled, an attacker with access to any Azure AD tenant can obtain a valid Microsoft-signed token and use it to enroll unauthorized devices and interact with Fleet's MDM management APIs. During device management, Fleet may expose sensitive enrollment secrets embedded in MDM command payloads, enabling further unauthorized access. Version 4.82.0 contains a patch. If an immediate upgrade is not possible, affected Fleet users should temporarily disable Windows MDM.

• CWE-290Authentication Bypass by SpoofingThis attack-focused weakness is caused by incorrectly implemented authentication schemes that are subject to spoofing attacks.