CVE-2025-30386
📋 TL;DR
A use-after-free vulnerability in Microsoft Office allows attackers to execute arbitrary code on affected systems by exploiting memory corruption after freeing. This affects users running vulnerable versions of Microsoft Office applications. Attackers could gain control of the system with the privileges of the current user.
💻 Affected Systems
- Microsoft Office
📦 What is this software?
365 Apps by Microsoft
365 Apps by Microsoft
Office by Microsoft
Office by Microsoft
Office by Microsoft
Office by Microsoft
Office 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
Full system compromise with attacker gaining administrative privileges, data theft, ransomware deployment, and persistent backdoor installation.
Likely Case
Local privilege escalation leading to data exfiltration, credential harvesting, and lateral movement within the network.
If Mitigated
Limited impact with application crash or denial of service if exploit fails or security controls block execution.
🎯 Exploit Status
Exploitation requires user interaction with malicious content. No public exploit code available at this time.
🛠️ Fix & Mitigation
✅ Official Fix
Patch Version: Check Microsoft Security Update Guide for specific patch versions
Vendor Advisory: https://msrc.microsoft.com/update-guide/vulnerability/CVE-2025-30386
Restart Required: Yes
Instructions:
1. Open Microsoft Office application
2. Go to File > Account > Update Options
3. Select 'Update Now'
4. Restart Office applications when prompted
5. Alternatively, apply Windows Update for Office patches
🔧 Temporary Workarounds
Disable Office macro execution
windowsPrevents execution of malicious macros that could trigger the vulnerability
Set Group Policy: Computer Configuration > Administrative Templates > Microsoft Office 2016 > Security Settings > Trust Center > Disable all macros without notification
Use Office Protected View
windowsOpen documents from untrusted sources in Protected View to prevent automatic code execution
Ensure Protected View is enabled in Trust Center settings
🧯 If You Can't Patch
- Implement application whitelisting to block unauthorized Office execution
- Use network segmentation to isolate Office systems from critical assets
🔍 How to Verify
Check if Vulnerable:
Check Office version against patched versions in Microsoft Security Update GuideCheck Version:
In Office application: File > Account > About [Application Name]Verify Fix Applied:
Verify Office version is updated to patched version and Windows Update shows no pending Office updates📡 Detection & Monitoring
Log Indicators:
- Office application crashes with memory access violations
- Unusual Office child process creation
- Office loading unexpected DLLs
Network Indicators:
- Office applications making unexpected outbound connections after document opening
SIEM Query:
EventID=1000 OR EventID=1001 Source=Application Error AND Process Name contains WINWORD.EXE OR EXCEL.EXE