EUVD-2026-29657
GHSA-mm5g-hh2r-m789
Severity by source
AV:L/AC:L/PR:L/UI:N/S:U/C:H/I:H/A:H
Local privilege escalation from an existing low-privileged account (AV:L, PR:L, AC:L, UI:N) with no scope change but total SYSTEM compromise giving high C/I/A.
Primary rating from NVD.
CVSS VectorNVD
Lifecycle Timeline
2DescriptionCVE.org
Improper access control in Azure Connected Machine Agent allows an authorized attacker to elevate privileges locally.
AnalysisAI
Local privilege escalation in Microsoft's Azure Connected Machine Agent (versions 1.0.0 through 1.62) allows a low-privileged authenticated user on an Azure Arc-enabled machine to gain SYSTEM-level privileges by abusing an improper access control weakness. Microsoft has released a fixed build (1.63) and this is currently classified with no known exploitation (SSVC: none), consistent with an EPSS score of just 0.04%; no public exploit identified at time of analysis. The flaw is tagged as an authentication bypass and carries full technical impact (total) across confidentiality, integrity, and availability.
Technical ContextAI
The Azure Connected Machine Agent (azcmagent) is the software installed on non-Azure and on-premises servers to onboard them into Azure Arc, giving Azure control-plane management, policy, monitoring, and extension execution over hybrid machines. Because the agent runs privileged services and manages extensions locally, weaknesses in how it enforces access to its resources are high-impact. The root cause is CWE-284 (Improper Access Control): the agent fails to correctly restrict which local principals can perform a privileged operation or access a protected resource, letting a lower-privileged user cross a trust boundary. The affected component is identified by CPE cpe:2.3:a:microsoft:azure_connected_machine_agent, spanning all versions prior to 1.63.
RemediationAI
Vendor-released patch: upgrade the Azure Connected Machine Agent to version 1.63 or later on all Azure Arc-enabled machines, as directed by the Microsoft advisory at https://msrc.microsoft.com/update-guide/vulnerability/CVE-2026-40381. Where automatic agent updates are enabled via Azure Arc, verify the rollout reaches all managed hosts and confirm the reported agent version is 1.63+. Because exploitation requires an authenticated local foothold, a strong compensating control until patching completes is to tightly restrict and monitor interactive and remote local logon rights on Arc-managed servers (limit who has any local account access), which reduces the pool of principals able to trigger the flaw; the trade-off is operational friction for administrators and support staff who legitimately need local access. Additional third-party notes are available at https://vuldb.com/vuln/363188.
Local privilege escalation in Azure Connected Machine Agent exploits a stack-based buffer overflow, enabling authenticat
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External control of file name or path in Azure Arc allows an authorized attacker to elevate privileges locally. Rated hi
Improper access control in Azure Windows Virtual Machine Agent allows an authorized attacker to elevate privileges local
Same weakness CWE-284 – Improper Access Control
View allSame technique Authentication Bypass
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External POC / Exploit Code
Leaving vuln.today