CVE-2026-20944
📋 TL;DR
This vulnerability allows an attacker to read memory outside the intended buffer in Microsoft Office Word, potentially leading to arbitrary code execution. Attackers could exploit this by tricking users into opening malicious Word documents. All users running vulnerable versions of Microsoft Word are affected.
💻 Affected Systems
- Microsoft Office Word
- Microsoft 365 Apps
- Office LTSC
⚠️ Risk & Real-World Impact
Worst Case
Full system compromise with attacker gaining complete control over the victim's computer, enabling data theft, ransomware deployment, or persistent backdoor installation.
Likely Case
Local privilege escalation or information disclosure from memory, potentially leading to credential theft or lateral movement within the network.
If Mitigated
Application crash (denial of service) without code execution if memory protections like ASLR/DEP are effective.
🎯 Exploit Status
Requires user to open malicious document. No public exploit code available at this time.
🛠️ Fix & Mitigation
✅ Official Fix
Patch Version: Check Microsoft Security Update Guide for specific version numbers
Vendor Advisory: https://msrc.microsoft.com/update-guide/vulnerability/CVE-2026-20944
Restart Required: Yes
Instructions:
1. Open any Office application. 2. Go to File > Account > Update Options > Update Now. 3. For enterprise deployments, deploy through Microsoft Endpoint Configuration Manager or equivalent patch management system.
🔧 Temporary Workarounds
Disable Office macro execution
windowsPrevents malicious documents from executing code through macros
Set Group Policy: Computer Configuration > Administrative Templates > Microsoft Office 2016 > Security Settings > Trust Center > Block macros from running in Office files from the Internet
Use Microsoft Office Viewer
allOpen documents in read-only mode using Office Viewer instead of full Word application
🧯 If You Can't Patch
- Implement application whitelisting to block unauthorized Word execution
- Deploy email filtering to block suspicious Word attachments and enable sandboxing for document analysis
🔍 How to Verify
Check if Vulnerable:
Check Word version against patched versions in Microsoft advisory. Vulnerable if running unpatched version.Check Version:
In Word: File > Account > About Word (Windows) or Word > About Word (macOS)Verify Fix Applied:
Verify Word version matches or exceeds patched version listed in Microsoft Security Update Guide.📡 Detection & Monitoring
Log Indicators:
- Word application crashes with memory access violations
- Unexpected child processes spawned from WINWORD.EXE
Network Indicators:
- Unusual outbound connections following Word document opening
- DNS queries to suspicious domains after document access
SIEM Query:
source="*security*" event_id=1000 process_name="WINWORD.EXE" | search "exception code"="0xc0000005"