CVE-2026-21514
📋 TL;DR
This vulnerability in Microsoft Office Word allows attackers to bypass local security features by manipulating untrusted inputs. It affects users running vulnerable versions of Microsoft Word on Windows systems. The flaw could enable unauthorized access or privilege escalation on affected systems.
💻 Affected Systems
- Microsoft Office Word
- Microsoft 365 Apps
- Microsoft Office LTSC
📦 What is this software?
365 Apps by Microsoft
365 Apps by Microsoft
Office Long Term Servicing Channel by Microsoft
View all CVEs affecting Office Long Term Servicing Channel →
Office Long Term Servicing Channel by Microsoft
View all CVEs affecting Office Long Term Servicing Channel →
Office Long Term Servicing Channel by Microsoft
View all CVEs affecting Office Long Term Servicing Channel →
Office Long Term Servicing Channel by Microsoft
View all CVEs affecting Office Long Term Servicing Channel →
⚠️ Risk & Real-World Impact
Worst Case
Complete system compromise through privilege escalation leading to data theft, malware installation, or lateral movement within the network.
Likely Case
Local privilege escalation allowing attackers to gain higher privileges than intended, potentially accessing sensitive documents or system resources.
If Mitigated
Limited impact with proper user account controls, application sandboxing, and restricted user privileges in place.
🎯 Exploit Status
Requires local access or user interaction with malicious Word document. Likely involves social engineering to deliver payload.
🛠️ Fix & Mitigation
✅ Official Fix
Patch Version: To be determined from Microsoft's monthly security updates
Vendor Advisory: https://msrc.microsoft.com/update-guide/vulnerability/CVE-2026-21514
Restart Required: Yes
Instructions:
1. Open Microsoft Word. 2. Go to File > Account > Update Options > Update Now. 3. Alternatively, use Windows Update: Settings > Update & Security > Windows Update > Check for updates. 4. Install all available Office updates. 5. Restart computer if prompted.
🔧 Temporary Workarounds
Disable macros and ActiveX
windowsPrevent execution of potentially malicious content in Word documents
File > Options > Trust Center > Trust Center Settings > Macro Settings > Disable all macros without notification
File > Options > Trust Center > Trust Center Settings > ActiveX Settings > Disable all controls without notification
Use Protected View
windowsForce all documents from internet to open in Protected View
File > Options > Trust Center > Trust Center Settings > Protected View > Enable all Protected View options
🧯 If You Can't Patch
- Implement application whitelisting to restrict which applications can run
- Use Microsoft Defender Application Guard for Office to isolate untrusted documents
🔍 How to Verify
Check if Vulnerable:
Check Word version: File > Account > About Word. Compare with Microsoft's patched version list.Check Version:
winword.exe /? (in command prompt) or check via Control Panel > Programs > Programs and FeaturesVerify Fix Applied:
Verify Word has updated to latest version and check that Windows Update shows no pending Office updates.📡 Detection & Monitoring
Log Indicators:
- Windows Event Logs: Security events showing privilege escalation attempts
- Office telemetry logs showing abnormal document processing
Network Indicators:
- Unusual outbound connections from Word process
- Downloads of suspicious Office templates or documents
SIEM Query:
EventID=4688 AND ProcessName="WINWORD.EXE" AND NewProcessName contains "cmd" OR "powershell"