CVE-2025-26633
📋 TL;DR
CVE-2025-26633 is a security feature bypass vulnerability in Microsoft Management Console (MMC) that allows a local attacker to circumvent security controls through improper input neutralization. This affects systems running vulnerable versions of Windows where MMC is present. Attackers must have local access to exploit this vulnerability.
💻 Affected Systems
- Microsoft Management Console
- Windows operating systems with MMC
📦 What is this software?
Windows 10 1507 by Microsoft
Windows 10 1507 by Microsoft
Windows 10 1607 by Microsoft
Windows 10 1607 by Microsoft
Windows 10 1809 by Microsoft
Windows 10 1809 by Microsoft
Windows 10 21h2 by Microsoft
Windows 10 21h2 by Microsoft
Windows 10 21h2 by Microsoft
Windows 10 22h2 by Microsoft
Windows 10 22h2 by Microsoft
Windows 10 22h2 by Microsoft
Windows 11 22h2 by Microsoft
Windows 11 22h2 by Microsoft
Windows 11 23h2 by Microsoft
Windows 11 23h2 by Microsoft
Windows 11 24h2 by Microsoft
Windows 11 24h2 by Microsoft
⚠️ Risk & Real-World Impact
Worst Case
An attacker with local access could bypass security features to gain elevated privileges, modify system configurations, or disable security controls, potentially leading to full system compromise.
Likely Case
Local attackers bypass specific security restrictions within MMC to perform unauthorized administrative actions or access restricted functionality.
If Mitigated
With proper access controls and patching, impact is limited to failed exploitation attempts with no privilege escalation.
🎯 Exploit Status
Exploitation requires local access and knowledge of the specific security feature bypass technique. No public exploit code is currently available.
🛠️ Fix & Mitigation
✅ Official Fix
Patch Version: Check Microsoft Security Update Guide for specific KB numbers
Vendor Advisory: https://msrc.microsoft.com/update-guide/vulnerability/CVE-2025-26633
Restart Required: No
Instructions:
1. Apply the latest Windows security updates from Microsoft. 2. Verify the update is installed via Windows Update or WSUS. 3. No system restart is typically required for MMC updates.
🔧 Temporary Workarounds
Restrict local access to MMC
allLimit which users can access Microsoft Management Console through Group Policy or local security settings
gpedit.msc -> User Configuration -> Administrative Templates -> Windows Components -> Microsoft Management Console
🧯 If You Can't Patch
- Implement strict least privilege access controls to limit who can run MMC
- Monitor for unusual MMC activity and implement application whitelisting
🔍 How to Verify
Check if Vulnerable:
Check Windows Update history for the specific KB patch mentioned in Microsoft's advisoryCheck Version:
wmic qfe list | findstr KB[number] or Get-Hotfix -Id KB[number] in PowerShellVerify Fix Applied:
Verify the security update is installed via 'Settings > Update & Security > View update history'📡 Detection & Monitoring
Log Indicators:
- Unusual MMC process execution by non-admin users
- Security event logs showing privilege escalation attempts
Network Indicators:
- Not applicable - local exploitation only
SIEM Query:
EventID=4688 AND ProcessName LIKE '%mmc.exe%' AND SubjectUserName NOT IN (admin_users_list)🔗 References
- https://msrc.microsoft.com/update-guide/vulnerability/CVE-2025-26633
- https://www.vicarius.io/vsociety/posts/cve-2025-26633-security-feature-bypass-in-microsoft-management-console-detection-script
- https://www.vicarius.io/vsociety/posts/cve-2025-26633-security-feature-bypass-in-microsoft-management-console-mitigation-script
- https://www.cisa.gov/known-exploited-vulnerabilities-catalog?field_cve=CVE-2025-26633
