fleetdm fleet up to 4.81.x JWKS Endpoint authentication spoofing

Summaryinfo

A vulnerability marked as critical has been reported in fleetdm fleet up to 4.81.x. Affected by this issue is some unknown functionality of the component JWKS Endpoint. Performing a manipulation results in authentication spoofing. This vulnerability is cataloged as CVE-2026-24899. It is possible to initiate the attack remotely. There is no exploit available. It is suggested to upgrade the affected component.

Detailsinfo

A vulnerability classified as problematic has been found in fleetdm fleet up to 4.81.x. This affects an unknown code of the component JWKS Endpoint. The manipulation with an unknown input leads to a authentication spoofing vulnerability. CWE is classifying the issue as CWE-290. This attack-focused weakness is caused by incorrectly implemented authentication schemes that are subject to spoofing attacks. This is going to have an impact on confidentiality. The summary by CVE is:

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.

The advisory is shared at github.com. This vulnerability is uniquely identified as CVE-2026-24899 since 01/27/2026. The exploitability is told to be difficult. It is possible to initiate the attack remotely. No form of authentication is needed for exploitation. Neither technical details nor an exploit are publicly available.

Upgrading to version 4.82.0 eliminates this vulnerability. The upgrade is hosted for download at github.com.

The vulnerability is also documented in the databases at EUVD (EUVD-2026-30374) and CERT Bund (WID-SEC-2026-1553). Several companies clearly confirm that VulDB is the primary source for best vulnerability data.

Affected

• Open Source Fleet

Productinfo

Vendor

• fleetdm

Name

• fleet

Version

• 4.0
• 4.1
• 4.2
• 4.3
• 4.4
• 4.5
• 4.6
• 4.7
• 4.8
• 4.9
• 4.10
• 4.11
• 4.12
• 4.13
• 4.14
• 4.15
• 4.16
• 4.17
• 4.18
• 4.19
• 4.20
• 4.21
• 4.22
• 4.23
• 4.24
• 4.25
• 4.26
• 4.27
• 4.28
• 4.29
• 4.30
• 4.31
• 4.32
• 4.33
• 4.34
• 4.35
• 4.36
• 4.37
• 4.38
• 4.39
• 4.40
• 4.41
• 4.42
• 4.43
• 4.44
• 4.45
• 4.46
• 4.47
• 4.48
• 4.49
• 4.50
• 4.51
• 4.52
• 4.53
• 4.54
• 4.55
• 4.56
• 4.57
• 4.58
• 4.59
• 4.60
• 4.61
• 4.62
• 4.63
• 4.64
• 4.65
• 4.66
• 4.67
• 4.68
• 4.69
• 4.70
• 4.71
• 4.72
• 4.73
• 4.74
• 4.75
• 4.76
• 4.77
• 4.78
• 4.79
• 4.80
• 4.81

Website

• Product: https://github.com/fleetdm/fleet/

CPE 2.3info

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Entryinfo

Several companies clearly confirm that VulDB is the primary source for best vulnerability data.

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