CVE-2025-26627 Overview
CVE-2025-26627 is a command injection vulnerability in Microsoft Azure Arc. The flaw stems from improper neutralization of special elements used in a command [CWE-77]. An authorized local attacker can exploit this weakness to elevate privileges on affected systems.
Microsoft published the advisory on March 11, 2025. The vulnerability carries a CVSS 3.1 score of 7.0 and requires local access with low privileges. Successful exploitation impacts confidentiality, integrity, and availability. No public proof-of-concept exploits have been observed, and the vulnerability is not listed in the CISA Known Exploited Vulnerabilities catalog.
Critical Impact
A low-privileged local user can inject crafted command sequences into Azure Arc components to gain higher privileges on the host system.
Affected Products
- Microsoft Azure Arc (all versions prior to the March 2025 security update)
- Azure Connected Machine Agent components deployed on managed servers
- Hybrid infrastructure hosts registered with Azure Arc
Discovery Timeline
- 2025-03-11 - CVE-2025-26627 published to NVD
- 2025-03-11 - Microsoft releases security update guidance
- 2026-06-17 - Last updated in NVD database
Technical Details for CVE-2025-26627
Vulnerability Analysis
CVE-2025-26627 is a command injection flaw (CWE-77) in Azure Arc. Azure Arc extends Azure management to on-premises servers, Kubernetes clusters, and multi-cloud resources through an agent that runs with elevated privileges. When the agent processes input containing shell metacharacters without proper sanitization, an attacker can append arbitrary commands to legitimate operations.
The vulnerability requires local access and low privileges. Attack complexity is high, indicating the exploit path depends on specific conditions such as timing, configuration state, or the presence of certain scheduled operations. Once these conditions are met, the injected commands execute in the security context of the Azure Arc agent, which typically runs with system-level rights.
Root Cause
The root cause is insufficient input validation in code paths that construct command strings passed to a shell or command interpreter. Special elements such as semicolons, pipes, backticks, or newline characters are not neutralized before the string is executed. This allows an attacker-supplied value to break out of the intended command context.
Attack Vector
Exploitation requires an authenticated local user on the Azure Arc-managed host. The attacker supplies crafted input to an Azure Arc component or configuration entry that is later consumed by a privileged process. When the vulnerable code invokes the underlying shell, the injected payload executes with the elevated permissions of the Azure Arc agent. This yields local privilege escalation from a low-privileged account to a higher trust level.
No verified public exploit code is currently available. See the Microsoft Security Update CVE-2025-26627 advisory for vendor-supplied technical details.
Detection Methods for CVE-2025-26627
Indicators of Compromise
- Unexpected child processes spawned by the Azure Connected Machine Agent (himds, gcarcservice, or extd) invoking shells such as cmd.exe, powershell.exe, or /bin/sh.
- Command-line arguments to Azure Arc processes containing shell metacharacters (;, |, &, `, $().
- New local accounts, group membership changes, or scheduled tasks created shortly after Azure Arc agent activity.
Detection Strategies
- Baseline the expected process tree of the Azure Arc agent and alert on deviations, particularly shell interpreters launched as children.
- Monitor Azure Arc configuration files and extension inputs for suspicious characters that indicate injection attempts.
- Correlate local logon events with subsequent privileged process activity originating from Arc-managed components.
Monitoring Recommendations
- Forward Azure Arc agent logs and Windows/Linux process telemetry to a centralized SIEM for behavioral analysis.
- Enable command-line auditing (Windows Event ID 4688, Linux execve auditing) on all Azure Arc-managed hosts.
- Review Azure Activity Log entries for unauthorized changes to Arc-enabled resource configurations.
How to Mitigate CVE-2025-26627
Immediate Actions Required
- Apply the security update referenced in the Microsoft Security Update CVE-2025-26627 advisory to all Azure Arc-managed hosts.
- Inventory all systems running the Azure Connected Machine Agent and confirm the installed version reflects the patched release.
- Restrict local logon rights on Azure Arc-managed hosts to reduce the pool of accounts that can attempt exploitation.
Patch Information
Microsoft addressed CVE-2025-26627 in the March 2025 security update cycle. Administrators should consult the Microsoft Security Update guide for the specific fixed version of the Azure Connected Machine Agent and follow standard update procedures for both Windows and Linux hosts.
Workarounds
- Limit local access to Azure Arc-managed hosts using least-privilege principles and just-in-time access controls.
- Enforce strict RBAC on Azure Arc resources so that only trusted principals can modify agent configurations or extensions.
- Enable enhanced logging on Arc-enabled servers to detect anomalous command execution patterns until patching is complete.
# Check Azure Connected Machine Agent version on Linux
azcmagent show
# Check on Windows (PowerShell)
& "$env:ProgramFiles\AzureConnectedMachineAgent\azcmagent.exe" show
Disclaimer: This content was generated using AI. While we strive for accuracy, please verify critical information with official sources.
