Fleet Windows MDM Azure AD JWT Authentication Bypass
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.
If an immediate upgrade is not possible, affected Fleet users should temporarily disable Windows MDM.
If you have any questions or comments about this advisory:
Email us at [security@fleetdm.com](mailto:[email protected])
Join #fleet in [osquery Slack](https://join.slack.com/t/osquery/shared_invite/zt-h29zm0gk-s2DBtGUTW4CFel0f0IjTEw)
We thank @zaddy6 for responsibly reporting this issue.
This issue can be reached over the network, attack complexity is low, an attacker needs no privileges on the target. No user interaction is required. The scope is unchanged, so the impact stays within the vulnerable component. Rated impact: confidentiality high, integrity none, availability none.
The score comes from this vector: CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:H/I:N/A:N
CVE-2026-24899 is classified as CWE-290: Authentication Bypass by Spoofing. Identity is inferred from something an attacker can forge, such as a header or address.
CVE-2026-24899 is recorded against 2 packages.
Published on 14 May 2026 and last revised on 17 June 2026. No public exploit is currently recorded for this entry. Record sourced from NVD.
fleet has other advisories on record. If you are patching this one, these are worth checking on the same host:
These advisories are the same class of weakness (CWE-290: Authentication Bypass by Spoofing) in other software:
Details
CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:H/I:N/A:N
Affected Packages
| Software | From version | Fixed in |
|---|---|---|
| fleet | — | 4.82.0 |
| github.com/fleetdm/fleet/v4 | — | — |
References
Similar Threats
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CVE-2026-24899 is rated CVSS 8.0 High. BotEraser scans your installation against known CVE records and tells you whether this vulnerability applies to the versions you actually run.
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