CVE-2026-27914 Overview
CVE-2026-27914 is an improper access control vulnerability in the Microsoft Management Console (MMC) that enables a locally authenticated attacker to elevate privileges on affected Windows systems. The flaw is tracked under CWE-284: Improper Access Control and affects a broad set of Windows client and server releases. Microsoft has published guidance through the Microsoft Security Update CVE-2026-27914 advisory.
Successful exploitation grants the attacker high impact on confidentiality, integrity, and availability of the targeted host. The vulnerability does not require user interaction and can be triggered with low privileges already held on the system.
Critical Impact
A standard local user can leverage Microsoft Management Console to gain higher-privileged code execution, potentially reaching SYSTEM-level control on unpatched Windows endpoints and servers.
Affected Products
- Microsoft Windows 10 (versions 1607, 1809, 21H2, 22H2)
- Microsoft Windows 11 (versions 23H2, 24H2, 25H2, 26H1)
- Microsoft Windows Server 2012, 2012 R2, 2016, 2019, 2022, 2022 23H2, and 2025
Discovery Timeline
- 2026-04-14 - CVE-2026-27914 published to NVD
- 2026-04-22 - Last updated in NVD database
Technical Details for CVE-2026-27914
Vulnerability Analysis
The Microsoft Management Console (mmc.exe) hosts administrative snap-ins used to configure Windows components. CVE-2026-27914 results from improper access control within MMC, allowing a low-privileged but authenticated user to perform actions that should be restricted to higher-privileged principals. The attack is local and requires no user interaction, which makes it well-suited as a post-compromise privilege escalation primitive.
The weakness is classified as CWE-284: Improper Access Control. When MMC fails to correctly evaluate the caller's security context before performing privileged operations, an attacker can invoke functionality outside their assigned role. The end result is elevation to a higher integrity level, with full impact on confidentiality, integrity, and availability of the host.
The vulnerability currently has no public proof-of-concept and is not listed in the CISA Known Exploited Vulnerabilities catalog. The EPSS probability sits at 0.061%, indicating low predicted exploitation activity at this time.
Root Cause
The root cause is missing or incorrect authorization checks inside Microsoft Management Console code paths. MMC trusts inputs or state transitions that should be validated against the caller's token, enabling a standard user to perform operations reserved for administrators.
Attack Vector
Exploitation requires local access and valid credentials on the target system. An attacker with an interactive session or a foothold via phishing, malware, or compromised credentials launches a crafted interaction with MMC or one of its snap-ins. The flaw is then triggered to escalate privileges without prompting the user, providing a path from initial access to SYSTEM-level control on the endpoint.
No verified exploit code is publicly available. Refer to the Microsoft Security Update CVE-2026-27914 advisory for vendor-specific technical details.
Detection Methods for CVE-2026-27914
Indicators of Compromise
- Unexpected launches of mmc.exe by non-administrative users, particularly outside normal administrative workflows.
- Creation of child processes from mmc.exe that run with elevated tokens or SYSTEM integrity.
- Loading of unusual or unsigned snap-in DLLs by mmc.exe from user-writable directories.
- New scheduled tasks, services, or local accounts created shortly after MMC activity by a non-privileged user.
Detection Strategies
- Hunt for token elevation events where the parent process is mmc.exe and the originating user is not a member of local Administrators.
- Correlate Windows Security event ID 4688 (process creation) with 4672 (special privileges assigned) where MMC is in the chain.
- Baseline normal MMC snap-in usage in the environment, then alert on snap-ins that deviate from approved administrative tooling.
Monitoring Recommendations
- Enable command-line auditing and Sysmon process creation logging across Windows endpoints and servers.
- Forward MMC-related telemetry to a centralized analytics platform for cross-host correlation.
- Monitor for privilege escalation patterns immediately following authentication events from non-administrative accounts.
How to Mitigate CVE-2026-27914
Immediate Actions Required
- Apply the security update referenced in the Microsoft Security Update CVE-2026-27914 advisory to all affected Windows client and server versions.
- Prioritize patching of multi-user systems, jump hosts, and servers where standard users have interactive logon rights.
- Review local administrator group membership and remove unnecessary accounts to reduce blast radius.
Patch Information
Microsoft has issued vendor-supplied updates addressing CVE-2026-27914 across supported Windows 10, Windows 11, and Windows Server releases. Patch identifiers and KB articles for each platform are listed on the Microsoft Security Update CVE-2026-27914 page. Deploy via Windows Update, WSUS, Microsoft Intune, or your existing patch management workflow.
Workarounds
- Restrict interactive logon on sensitive servers to administrators only using Group Policy User Rights Assignment.
- Apply application control policies (Windows Defender Application Control or AppLocker) to limit which users can launch mmc.exe and load specific snap-ins.
- Reduce the number of standard users with local logon access to multi-tenant systems until patching is complete.
# Example AppLocker rule snippet to restrict mmc.exe to administrators
# Run in an elevated PowerShell session
New-AppLockerPolicy -RuleType Path -User "BUILTIN\Administrators" `
-Path "%SYSTEM32%\mmc.exe" -Action Allow |
Set-AppLockerPolicy -Merge
Disclaimer: This content was generated using AI. While we strive for accuracy, please verify critical information with official sources.
