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Vulnerability · Published Jan 21, 2026 · Assigned by GitHub_M

CVE-2026-22808Fleet Windows MDM endpoint has a Cross-site Scripting vulnerability

Medium 5.5

In plain English

A medium-severity cross-site scripting in fleet from fleetdm. There are no confirmed reports of exploitation so far. The chance it is exploited in the next 30 days is estimated at 0.2% (higher than 16% of all known vulnerabilities). Fixed versions are available - upgrade the affected package.

Severity (CVSS 4.0)5.5Medium
Exploit odds (30 days)0.2%top 83.7% of all CVEs
Exploited in the wildNo reportsCISA SSVC: none
Attack toolingNoneno public tooling known

Official 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.

Affected packages & fixed versions

EcosystemPackageFixed inAdvisory
Gogithub.com/fleetdm/fleet4.78.2GHSA-gfpw-jgvr-cw4j
Gogithub.com/fleetdm/fleet4.77.1GHSA-gfpw-jgvr-cw4j
Gogithub.com/fleetdm/fleet4.76.2GHSA-gfpw-jgvr-cw4j
Gogithub.com/fleetdm/fleet4.75.2GHSA-gfpw-jgvr-cw4j
Gogithub.com/fleetdm/fleet/v44.75.2, 4.76.2, 4.77.1, 4.78.2GO-2026-4336
Gogithub.com/fleetdm/fleet/v44.43.5-0.20260111020427-0e6c790803d1GHSA-gfpw-jgvr-cw4j

Affected products (as reported)

VendorProductVersions
fleetdm fleet >= 4.78.0, < 4.78.2>= 4.77.0, < 4.77.1>= 4.76.0, < 4.76.2< 4.53.3

Weakness: CWE-79 · Vector: 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

References