CVE-2025-54902
📋 TL;DR
An out-of-bounds read vulnerability in Microsoft Office Excel allows attackers to execute arbitrary code on affected systems by tricking users into opening malicious Excel files. This affects users running vulnerable versions of Microsoft Excel on Windows, macOS, and potentially other platforms where Office is supported.
💻 Affected Systems
- Microsoft Excel
- Microsoft Office suites containing Excel
📦 What is this software?
365 Apps by Microsoft
365 Apps by Microsoft
Excel by Microsoft
Excel 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 →
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 the same privileges as the logged-in user, potentially leading to data theft, ransomware deployment, or lateral movement within the network.
Likely Case
Local code execution with user-level privileges, enabling data exfiltration, credential theft, and installation of additional malware.
If Mitigated
Limited impact due to application sandboxing, antivirus detection, or user account restrictions preventing privilege escalation.
🎯 Exploit Status
Requires user interaction to open malicious Excel file. Exploit development requires understanding of Excel file format and memory corruption techniques.
🛠️ Fix & Mitigation
✅ Official Fix
Patch Version: To be specified in Microsoft Security Update
Vendor Advisory: https://msrc.microsoft.com/update-guide/vulnerability/CVE-2025-54902
Restart Required: Yes
Instructions:
1. Open any Office application
2. Go to File > Account > Update Options > Update Now
3. Alternatively, use Microsoft Update or Windows Update for system-wide updates
4. Restart computer after update installation
🔧 Temporary Workarounds
Disable Excel Protected View
windowsConfigure Excel to open files from untrusted sources in Protected View to prevent automatic code execution
Block .xls/.xlsx attachments
allConfigure email gateways to block or sandbox Excel file attachments
🧯 If You Can't Patch
- Restrict Excel file execution via application control policies (AppLocker/Windows Defender Application Control)
- Implement network segmentation to limit lateral movement from compromised workstations
🔍 How to Verify
Check if Vulnerable:
Check Excel version against patched version in Microsoft advisory. Vulnerable if running unpatched version.Check Version:
In Excel: File > Account > About Excel (Windows) or Excel > About Excel (macOS)Verify Fix Applied:
Verify Excel version matches or exceeds patched version specified in Microsoft advisory.📡 Detection & Monitoring
Log Indicators:
- Excel crash logs with memory access violations
- Windows Event Logs showing Excel process spawning unexpected child processes
Network Indicators:
- Unusual outbound connections from Excel process
- DNS requests to suspicious domains following Excel file opening
SIEM Query:
source="*excel*" AND (event_id=1000 OR process_creation_parent="excel.exe")