fleetdm fleet up to 4.78.2 signature verification

Summaryinfo

A vulnerability has been found in fleetdm fleet up to 4.53.2/4.75.1/4.76.1/4.77.0/4.78.2 and classified as very critical. The impacted element is an unknown function. Performing a manipulation results in signature verification. This vulnerability is identified as CVE-2026-23518. The attack can be initiated remotely. There is not any exploit available. The affected component should be upgraded.

Detailsinfo

A vulnerability classified as very critical has been found in fleetdm fleet up to 4.53.2/4.75.1/4.76.1/4.77.0/4.78.2. This affects an unknown part. The manipulation with an unknown input leads to a signature verification vulnerability. CWE is classifying the issue as CWE-347. The product does not verify, or incorrectly verifies, the cryptographic signature for data. This is going to have an impact on confidentiality, integrity, and availability. The summary by CVE is:

Fleet is open source device management software. In versions prior to 4.78.3, 4.77.1, 4.76.2, 4.75.2, and 4.53.3, a vulnerability in Fleet's Windows MDM enrollment flow could allow an attacker to submit forged authentication tokens that are not properly validated. Because JWT signatures were not verified, Fleet could accept attacker-controlled identity claims, enabling enrollment of unauthorized devices under arbitrary Azure AD user identities. Versions 4.78.3, 4.77.1, 4.76.2, 4.75.2, and 4.53.3 fix the issue. 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-2026-23518 since 01/13/2026. The exploitability is told to be easy. 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. The price for an exploit might be around USD $0-$5k at the moment (estimation calculated on 02/27/2026).

Upgrading to version 4.53.3, 4.75.2, 4.76.2, 4.77.1 or 4.78.3 eliminates this vulnerability. Applying the patch e225ef57912c8f4ac8977e24b5ebe1d9fd875257 is able to eliminate this problem. The bugfix is ready for download at github.com. The best possible mitigation is suggested to be upgrading to the latest version.

The vulnerability is also documented in the vulnerability database at EUVD (EUVD-2026-3348). If you want to get the best quality for vulnerability data then you always have to consider VulDB.

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
• 4.53.0
• 4.53.1
• 4.53.2
• 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
• 4.75.0
• 4.75.1
• 4.76
• 4.76.0
• 4.76.1
• 4.77.0
• 4.78.0
• 4.78.1
• 4.78.2

License

• open-source

Website

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

CPE 2.3info

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CPE 2.2info

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Entryinfo

If you want to get the best quality for vulnerability data then you always have to consider VulDB.

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