CVE-2025-47957
📋 TL;DR
This vulnerability is a use-after-free memory corruption flaw in Microsoft Office Word that allows an attacker to execute arbitrary code on a victim's system. It affects users who open malicious Word documents. The attacker must trick a user into opening a specially crafted document.
💻 Affected Systems
- Microsoft Office Word
📦 What is this software?
365 Apps by Microsoft
⚠️ Risk & Real-World Impact
Worst Case
Full system compromise with attacker gaining complete control over the victim's computer, potentially leading to data theft, ransomware deployment, or lateral movement within the network.
Likely Case
Local code execution with the privileges of the current user, allowing data access, installation of malware, or persistence mechanisms.
If Mitigated
Limited impact if proper application sandboxing, exploit mitigations, and least privilege principles are enforced, potentially containing the exploit to the Word process.
🎯 Exploit Status
Exploitation requires user interaction (opening a document). Use-after-free vulnerabilities often require precise memory manipulation, making reliable exploitation moderately complex.
🛠️ Fix & Mitigation
✅ Official Fix
Patch Version: Check Microsoft's monthly security updates for Office; specific version depends on your Office release channel.
Vendor Advisory: https://msrc.microsoft.com/update-guide/vulnerability/CVE-2025-47957
Restart Required: Yes
Instructions:
1. Open any Office application. 2. Go to File > Account > Update Options > Update Now. 3. Alternatively, use Windows Update for Microsoft 365 Apps or download patches from Microsoft Update Catalog. 4. Restart the system if prompted.
🔧 Temporary Workarounds
Block Office macros from the internet
windowsPrevents execution of macros in documents from untrusted sources, which could be used to trigger the vulnerability.
Group Policy: Computer Configuration > Administrative Templates > Microsoft Word 2016 > Word Options > Security > Trust Center > Block macros from running in Office files from the Internet
Use Microsoft Office Viewer
windowsOpen documents in read-only mode using Microsoft Office Viewer or protected view to prevent code execution.
🧯 If You Can't Patch
- Restrict Word document execution via application control policies (e.g., AppLocker, WDAC) to allow only trusted sources.
- Educate users to never open Word documents from untrusted or unexpected sources, especially via email attachments.
🔍 How to Verify
Check if Vulnerable:
Check Office version against patched versions listed in Microsoft's security advisory. Unpatched versions are vulnerable.Check Version:
In Word: File > Account > About Word. Or PowerShell: Get-ItemProperty -Path "HKLM:\Software\Microsoft\Office\ClickToRun\Configuration" -Name "VersionToReport"Verify Fix Applied:
Verify Office version matches or exceeds the patched version specified in Microsoft's advisory after applying updates.📡 Detection & Monitoring
Log Indicators:
- Windows Event Logs: Application crashes (Event ID 1000) for WINWORD.EXE with exception codes like 0xC0000005 (access violation)
- Antivirus/EDR alerts for malicious Office documents or exploit attempts
Network Indicators:
- Unusual outbound connections from Word process post-document opening
- Downloads of suspicious documents from external sources
SIEM Query:
source="*windows*" event_id=1000 process_name="WINWORD.EXE" exception_code="0xC0000005" | stats count by host