CVE-2025-26630
📋 TL;DR
A use-after-free vulnerability in Microsoft Office Access allows attackers to execute arbitrary code on vulnerable systems by tricking users into opening malicious Access files. This affects organizations using Microsoft Access with unpatched versions, potentially leading to full system compromise.
💻 Affected Systems
- Microsoft Office Access
📦 What is this software?
365 Apps by Microsoft
Access by Microsoft
Office by Microsoft
⚠️ Risk & Real-World Impact
Worst Case
Complete system takeover with administrative privileges, data theft, ransomware deployment, and lateral movement across the network.
Likely Case
Local privilege escalation leading to data exfiltration, credential harvesting, and persistence establishment on the compromised machine.
If Mitigated
Limited impact due to application sandboxing, user privilege restrictions, and network segmentation preventing lateral movement.
🎯 Exploit Status
Requires social engineering to deliver malicious file and user interaction to open it.
🛠️ Fix & Mitigation
✅ Official Fix
Patch Version: To be specified in Microsoft's monthly security updates
Vendor Advisory: https://msrc.microsoft.com/update-guide/vulnerability/CVE-2025-26630
Restart Required: No
Instructions:
1. Open Microsoft Office applications. 2. Go to File > Account > Update Options > Update Now. 3. Apply latest security updates from Windows Update. 4. Verify update installation.
🔧 Temporary Workarounds
Block Access file extensions
allPrevent execution of Access database files via email filters and endpoint protection
Disable macros and ActiveX
windowsConfigure Office security settings to disable potentially dangerous content
🧯 If You Can't Patch
- Restrict Access usage to trusted users only
- Implement application whitelisting to block unauthorized Access execution
🔍 How to Verify
Check if Vulnerable:
Check Office version against patched versions in Microsoft advisoryCheck Version:
Open Access > File > Account > About AccessVerify Fix Applied:
Verify Office build number matches or exceeds patched version📡 Detection & Monitoring
Log Indicators:
- Unusual Access process creation, crash logs from Access.exe, suspicious file opens
Network Indicators:
- Unexpected outbound connections from Access processes
SIEM Query:
Process creation where parent_process contains 'Access.exe' AND command_line contains suspicious patterns