CVE-2026-24899
Fleet Windows MDM Azure AD JWT Authentication Bypass
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.
INFO
Published Date :
May 14, 2026, 8:17 p.m.
Last Modified :
Oct. 26, 2026, 2:10 p.m.
Remotely Exploit :
Yes !
Source :
[email protected]
CVSS Scores
| Score | Version | Severity | Vector | Exploitability Score | Impact Score | Source |
|---|---|---|---|---|---|---|
| CVSS | 134c704f-9b21-4f2e-91b3-4a467353bcc0 | |||||
| CVSS 3.1 | HIGH | [email protected] | ||||
| CVSS 4.0 | HIGH | [email protected] |
Solution
- Update Fleet to version 4.82.0 or newer.
- Temporarily disable Windows MDM if upgrade is not possible.
References to Advisories, Solutions, and Tools
Here, you will find a curated list of external links that provide in-depth
information, practical solutions, and valuable tools related to
CVE-2026-24899.
| URL | Resource |
|---|---|
| https://github.com/fleetdm/fleet/releases/tag/fleet-v4.82.0 | Release Notes |
| https://github.com/fleetdm/fleet/security/advisories/GHSA-ffg9-j72f-j6xm | Vendor Advisory |
CWE - Common Weakness Enumeration
While CVE identifies
specific instances of vulnerabilities, CWE categorizes the common flaws or
weaknesses that can lead to vulnerabilities. CVE-2026-24899 is
associated with the following CWEs:
Common Attack Pattern Enumeration and Classification (CAPEC)
Common Attack Pattern Enumeration and Classification
(CAPEC)
stores attack patterns, which are descriptions of the common attributes and
approaches employed by adversaries to exploit the CVE-2026-24899
weaknesses.
We scan GitHub repositories to detect new proof-of-concept exploits. Following list is a collection of public exploits and proof-of-concepts, which have been published on GitHub (sorted by the most recently updated).
Results are limited to the first 15 repositories due to potential performance issues.
The following list is the news that have been mention
CVE-2026-24899 vulnerability anywhere in the article.
The following table lists the changes that have been made to the
CVE-2026-24899 vulnerability over time.
Vulnerability history details can be useful for understanding the evolution of a vulnerability, and for identifying the most recent changes that may impact the vulnerability's severity, exploitability, or other characteristics.
-
CVE Translated by [email protected]
Oct. 26, 2026
Action Type Old Value New Value Added Translation Title: fleet de fleetdm, Description: Fleet es un software de gestión de dispositivos de código abierto. Antes de la versión 4.82.0, una vulnerabilidad en el flujo de inscripción MDM de Windows de Fleet permite que los tokens de autenticación de cualquier inquilino de Azure AD sean aceptados. Debido a que Fleet valida las firmas JWT utilizando el endpoint JWKS multi-inquilino de Microsoft pero no aplica las claims ’aud’ (audiencia) o ’iss’ (emisor), cualquier token de acceso de Azure AD firmado por Microsoft que contenga los ámbitos esperados puede ser utilizado para autenticarse en los endpoints MDM de Fleet. Si Windows MDM está habilitado, un atacante con acceso a cualquier inquilino de Azure AD puede obtener un token válido firmado por Microsoft y usarlo para inscribir dispositivos no autorizados e interactuar con las APIs de gestión MDM de Fleet. Durante la gestión de dispositivos, Fleet puede exponer secretos de inscripción sensibles incrustados en las cargas útiles de comandos MDM, lo que permite un acceso no autorizado adicional. La versión 4.82.0 contiene un parche. Si una actualización inmediata no es posible, los usuarios afectados de Fleet deberían deshabilitar temporalmente Windows MDM. -
CVE Modified by [email protected]
Jun. 17, 2026
Action Type Old Value New Value Added Affected [{'vendor': 'fleetdm', 'product': 'fleet', 'versions': [{'status': 'affected', 'version': '< 4.82.0'}]}] -
CVE Modified by 134c704f-9b21-4f2e-91b3-4a467353bcc0
Jun. 17, 2026
Action Type Old Value New Value Added SSVC {'id': 'CVE-2026-24899', 'role': 'CISA Coordinator', 'options': [{'exploitation': 'none'}, {'automatable': 'yes'}, {'technicalImpact': 'total'}], 'version': '2.0.3', 'timestamp': '2026-05-16T00:51:50.857273Z'} -
Initial Analysis by [email protected]
May. 26, 2026
Action Type Old Value New Value Added CVSS V3.1 AV:N/AC:L/PR:N/UI:N/S:U/C:H/I:N/A:N Added CPE Configuration OR *cpe:2.3:a:fleetdm:fleet:*:*:*:*:*:*:*:* versions up to (excluding) 4.82.0 Added Reference Type GitHub, Inc.: https://github.com/fleetdm/fleet/releases/tag/fleet-v4.82.0 Types: Release Notes Added Reference Type GitHub, Inc.: https://github.com/fleetdm/fleet/security/advisories/GHSA-ffg9-j72f-j6xm Types: Vendor Advisory -
New CVE Received by [email protected]
May. 14, 2026
Action Type Old Value New Value Added 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. Added CVSS V4.0 AV:N/AC:H/AT:P/PR:N/UI:N/VC:H/VI:N/VA:N/SC:N/SI:N/SA:N/E:X/CR:X/IR:X/AR:X/MAV:X/MAC:X/MAT:X/MPR:X/MUI:X/MVC:X/MVI:X/MVA:X/MSC:X/MSI:X/MSA:X/S:X/AU:X/R:X/V:X/RE:X/U:X Added CWE CWE-290 Added Reference https://github.com/fleetdm/fleet/releases/tag/fleet-v4.82.0 Added Reference https://github.com/fleetdm/fleet/security/advisories/GHSA-ffg9-j72f-j6xm