CVE-2026-24899 Fleet Windows MDM Azure AD JWT Authentication Bypass
Attackers can bypass authentication in Fleet's Windows MDM by using tokens from any Azure AD tenant, enabling unauthorized device enrollment and access to sensitive data.
- Exploited in the wild
- Not known
- Login needed
- Not needed
- Attackable
- Over the internet
- Victim action needed
- Not needed
- Fix
- Available
What is CVE-2026-24899?
CVE-2026-24899 is a high-severity authentication bypass vulnerability in fleetdm fleet, published on 14 May 2026. An attacker can exploit it over the internet without logging in, with no action from the victim.
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.
Weakness: CWE-290
Which versions are affected by CVE-2026-24899?
3 open source packages ship an affected version, including github.com/fleetdm/fleet/v4. It affects 1 product.
| Package | Affected | Fixed in |
|---|---|---|
github.com/fleetdm/fleet/v4 Go | All versions | 4.82.0 |
github.com/fleetdm/fleet/v4 Go | All versions | 4.82.0 |
github.com/fleetdm/fleet/v4 Go | All versions | 4.82.0 |
Products include Fleetdm Fleet.
How do I fix CVE-2026-24899?
Upgrade github.com/fleetdm/fleet/v4 to 4.82.0 or later.
Upgrade, and rotate credentials and sessions that may have been exposed. More about Authentication bypass.
Is CVE-2026-24899 being exploited?
There is no known exploitation of CVE-2026-24899 in the wild and no public exploit code.
Other vulnerabilities in fleetdm fleet
- CVE-2020-26276 SAML authentication vulnerability in Fleet
- CVE-2026-103264 Fleet before 4.87.0 Authentication Bypass via Device Identifiers
- CVE-2026-23518 Fleet has a JWT signature bypass vulnerability in Azure AD MDM enrollment
- CVE-2026-26062 Fleet server may terminate unexpectedly when handling certain gRPC requests
- CVE-2026-26061 Fleet's unbounded request body read allows remote Denial of Service
Sources
Also known as GHSA-ffg9-j72f-j6xm, GO-2026-5358.