fleetdm fleet up to 4.80.0 Device Management authentication spoofing

Summaryinfo

A vulnerability described as critical has been identified in fleetdm fleet up to 4.80.0. This affects an unknown part of the component Device Management Handler. Executing a manipulation can lead to authentication spoofing. This vulnerability is registered as CVE-2026-24000. It is possible to launch the attack remotely. No exploit is available. Upgrading the affected component is recommended.

Detailsinfo

A vulnerability classified as critical was found in fleetdm fleet up to 4.80.0. This vulnerability affects an unknown code block of the component Device Management Handler. The manipulation with an unknown input leads to a authentication spoofing vulnerability. The CWE definition for the vulnerability is CWE-290. This attack-focused weakness is caused by incorrectly implemented authentication schemes that are subject to spoofing attacks. As an impact it is known to affect confidentiality, integrity, and availability. CVE summarizes:

Fleet is open source device management software. Prior to version 4.80.1, Fleet trusted client-supplied IP address headers when determining the source IP for incoming requests. This allowed authenticated and unauthenticated clients to spoof their apparent IP address and bypass per-IP rate limiting controls. Fleet determines a client’s public IP address using HTTP headers such as X-Forwarded-For, X-Real-IP, and/or True-Client-IP. These headers were trusted without validation. An attacker could supply arbitrary values in these headers, causing Fleet to treat each request as originating from a different IP address. This could allow an attacker to bypass per-IP rate limits and increase the effectiveness of brute-force or password-spraying attempts against authentication endpoints. This issue does not allow authentication bypass, privilege escalation, data exposure, or remote code execution on its own. Version 4.80.1 contains a patch. As a workaround, run Fleet behind a trusted reverse proxy or load balancer that overwrites client IP headers.

The advisory is available at github.com. This vulnerability was named CVE-2026-24000 since 01/19/2026. The exploitation appears to be easy. The attack can be initiated remotely. No form of authentication is required for a successful exploitation. The technical details are unknown and an exploit is not available.

Upgrading to version 4.80.1 eliminates this vulnerability. The upgrade is hosted for download at github.com.

The vulnerability is also documented in the vulnerability database at CERT Bund (WID-SEC-2026-1553). If you want to get best quality of vulnerability data, you may have to visit VulDB.

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
• 4.80.0

Website

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

CPE 2.3info

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Entryinfo

If you want to get best quality of vulnerability data, you may have to visit VulDB.

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