CVE-2026-22808

Fleet Windows MDM endpoint has a Cross-site Scripting vulnerability

State: Published
Severity: 5.5 Medium
Published: Jan 21, 2026
Updated: Jan 22, 2026
Reserved: Jan 9, 2026

Description

fleetdm/fleet is open source device management software. Prior to versions 4.78.2, 4.77.1, 4.76.2, 4.75.2, and 4.53.3, if Windows MDM is enabled, an unauthenticated attacker can exploit this XSS vulnerability to steal a Fleet administrator's authentication token (FLEET::auth_token) from localStorage. This could allow unauthorized access to Fleet, including administrative access, visibility into device data, and modification of configuration. Versions 4.78.2, 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.

Scores

CVSS	Score	Vector	Source
4.0	5.5 Medium	CVSS:4.0/AV:N/AC:L/AT:P/PR:L/UI:P/VC:N/VI:N/VA:N/SC:H/SI:H/SA:H	GitHub_M

Weaknesses

CWE-79 Improper Neutralization of Input During Web Page Generation ('Cross-site Scripting')

Affected Products

Product	Versions
fleetfleetdm	>= 4.78.0, < 4.78.2Affected >= 4.77.0, < 4.77.1Affected >= 4.76.0, < 4.76.2Affected < 4.53.3Affected

References

https://github.com/fleetdm/fleet/security/advisories/GHSA-gfpw-jgvr-cw4j

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