Description
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.
Affected products
| Vendor | Product | Affected | Fixed |
|---|---|---|---|
| fleetdm | fleet | >= 4.78.0, < 4.78.3, >= 4.77.0, < 4.77.1, >= 4.76.0, < 4.76.2, >= 4.75.0, < 4.75.2, < 4.53.3 | — |
Fixed in Linux distributions
Distributions backport fixes, so the version that fixes this vulnerability differs per release — upgrade to at least the version shown. From the distributions' security trackers and advisories.
openSUSE
Security tracker ↗| Release | Package | Fixed in | Advisory |
|---|---|---|---|
| openSUSE Leap 16.0 | govulncheck-vulndb | 0.0.20260723T184607-160000.1.1 | openSUSE-SU-2026:21483-1 |
| openSUSE Leap 15.6 | govulncheck-vulndb | 0.0.20260205T172317-150000.1.146.1 | SUSE-SU-2026:0403-1 |
Affected packages
| Ecosystem | Package | Affected | Fixed | Record |
|---|---|---|---|---|
| Go | github.com/fleetdm/fleet | >= 4.78.0, < 4.78.3 | 4.78.3 | GHSA-63m5-974w-448v |
| Go | github.com/fleetdm/fleet | >= 4.77.0, < 4.77.1 | 4.77.1 | GHSA-63m5-974w-448v |
| Go | github.com/fleetdm/fleet | >= 4.76.0, < 4.76.2 | 4.76.2 | GHSA-63m5-974w-448v |
| Go | github.com/fleetdm/fleet | >= 4.75.0, < 4.75.2 | 4.75.2 | GHSA-63m5-974w-448v |
| Go | github.com/fleetdm/fleet | < 4.43.5-0.20260112202845-e225ef57912c | 4.43.5-0.20260112202845-e225ef57912c | GHSA-63m5-974w-448v |
| Go | github.com/fleetdm/fleet/v4 | >= 4.75.0, < 4.75.2 · >= 4.76.0, < 4.76.2 · >= 4.77.0, < 4.77.1 · >= 4.78.0, < 4.78.3 | 4.75.2, 4.76.2, 4.77.1, 4.78.3 | GO-2026-4335 |
Advisories 2
- openSUSE-SU-2026:21483-1 Security update for govulncheck-vulndb SUSE / openSUSE Security Updates · Jul 31, 2026
- SUSE-SU-2026:0403-1 Security update for govulncheck-vulndb SUSE / openSUSE Security Updates · Mar 23, 2026