Vulnerability · Published May 14, 2026 · Assigned by GitHub_M
CVE-2026-24899Fleet Windows MDM Azure AD JWT Authentication Bypass
High 8.2
In plain English
A high-severity authentication bypass by spoofing in fleet from fleetdm. There are no confirmed reports of exploitation so far. The chance it is exploited in the next 30 days is estimated at 0.4% (higher than 32% of all known vulnerabilities). Fixed versions are available - upgrade the affected package.
Official 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.
Affected packages & fixed versions
| Ecosystem | Package | Fixed in | Advisory |
|---|---|---|---|
| Go | github.com/fleetdm/fleet/v4 | 4.82.0 | GHSA-ffg9-j72f-j6xm |
| Go | github.com/fleetdm/fleet/v4 | 4.82.0 | GO-2026-5358 |
Affected products (as reported)
Weakness: CWE-290 · Vector: CVSS:4.0/AV:N/AC:H/AT:P/PR:N/UI:N/VC:H/VI:N/VA:N/SC:N/SI:N/SA:N
References
- https://github.com/fleetdm/fleet/security/advisories/GHSA-ffg9-j72f-j6xm x_refsource_CONFIRM
- https://github.com/fleetdm/fleet/releases/tag/fleet-v4.82.0 x_refsource_MISC