Fleet has a JWT signature bypass vulnerability in Azure AD MDM enrollment
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.
AI Insight
LLM-synthesized narrative grounded in this CVE's description and references.
Affected packages
Versions sourced from the GitHub Security Advisory.
| Package | Affected versions | Patched versions |
|---|---|---|
github.com/fleetdm/fleetGo | >= 4.78.0, < 4.78.3 | 4.78.3 |
github.com/fleetdm/fleetGo | >= 4.77.0, < 4.77.1 | 4.77.1 |
github.com/fleetdm/fleetGo | >= 4.76.0, < 4.76.2 | 4.76.2 |
github.com/fleetdm/fleetGo | >= 4.75.0, < 4.75.2 | 4.75.2 |
github.com/fleetdm/fleetGo | < 4.43.5-0.20260112202845-e225ef57912c | 4.43.5-0.20260112202845-e225ef57912c |
Affected products
3- ghsa-coords2 versionspkg:golang/github.com/fleetdm/fleetpkg:rpm/opensuse/govulncheck-vulndb&distro=openSUSE%20Leap%2015.6
>= 4.78.0, < 4.78.3+ 1 more
- (no CPE)range: >= 4.78.0, < 4.78.3
- (no CPE)range: < 0.0.20260205T172317-150000.1.146.1
Patches
Vulnerability mechanics
References
5- github.com/advisories/GHSA-63m5-974w-448vghsaADVISORY
- nvd.nist.gov/vuln/detail/CVE-2026-23518ghsaADVISORY
- github.com/fleetdm/fleet/commit/e225ef57912c8f4ac8977e24b5ebe1d9fd875257ghsax_refsource_MISCWEB
- github.com/fleetdm/fleet/security/advisories/GHSA-63m5-974w-448vghsax_refsource_CONFIRMWEB
- pkg.go.dev/vuln/GO-2026-4335ghsaWEB
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