Local privilege escalation via named-pipe impersonation
Published Sep 9, 2025 · Updated Feb 26, 2026
External path control in Microsoft Azure Connected Machine agent before 1.56 allows local users to gain SYSTEM privileges. The Windows update-check task trusts automatic-upgrade values returned by the himds named pipe without verifying its server owner, then downloads and executes an attacker-supplied installer as SYSTEM. Exploitation requires a local low-privileged user to stop the legitimate service through MSI repair, create the replacement pipe, and satisfy the scheduled update flow; successful exploitation runs arbitrary code with SYSTEM privileges.
Summary
What happened
External path control in Microsoft Azure Connected Machine agent before 1.56 allows local users to gain SYSTEM privileges. The Windows update-check task trusts automatic-upgrade values returned by the himds named pipe without verifying its server owner, then downloads and executes an attacker-supplied installer as SYSTEM. Exploitation requires a local low-privileged user to stop the legitimate service through MSI repair, create the replacement pipe, and satisfy the scheduled update flow; successful exploitation runs arbitrary code with SYSTEM privileges.
The record
- CVE
- CVE-2025-55316
- Published
- Sep 9, 2025
- Updated
- Feb 26, 2026
- Vendor
- Microsoft
- Product
- Azure Connected Machine agent
- Classifications
- CWE-73, T1068
- Attack vector
- local
- Privileges
- authenticated
Timeline
How it unfolded
- Sep 9, 2025CVE publishedPublication date reported by the CVE source.
- Feb 26, 2026Record updatedLatest update available in the CVE record.
Exploitability
Present is not the same as exploitable
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Is a vulnerable build present?
Compare these published version ranges with your installed build and any vendor patches.
- Affected versionversion=1.0.0 <1.56
What conditions does exploitation require?
What is affected?
Published CVSS scores
CVSS describes severity. EPSS estimates exploitation probability.
Attacks
What attackers are doing with it
Daily unique IPs observed by Shadowserver honeypots for known exploited vulnerabilities (KEVs). Missing observations do not establish an absence of attacks.
Weakness, pattern, technique
Public exploit references
- Reversec named-pipe impersonation proof of conceptfunctional · demonstrated
Labels summarize the accepted research assessment. They do not indicate a test against your environment.
Technologies
Your stack
See the directory against your own environment.
Your stack
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