CVE-2025-26645
📋 TL;DR
This vulnerability allows attackers to exploit relative path traversal in Remote Desktop Client to execute arbitrary code remotely. It affects systems running vulnerable versions of Microsoft Remote Desktop Client software. Attackers can leverage this over a network connection to compromise affected systems.
💻 Affected Systems
- Microsoft Remote Desktop Client
📦 What is this software?
Windows 10 1507 by Microsoft
Windows 10 1507 by Microsoft
Windows 10 1607 by Microsoft
Windows 10 1607 by Microsoft
Windows 10 1809 by Microsoft
Windows 10 1809 by Microsoft
Windows 10 21h2 by Microsoft
Windows 10 22h2 by Microsoft
Windows 11 22h2 by Microsoft
Windows 11 23h2 by Microsoft
Windows 11 24h2 by Microsoft
Windows App by Microsoft
⚠️ Risk & Real-World Impact
Worst Case
Full system compromise with remote code execution, data exfiltration, and lateral movement across the network.
Likely Case
Unauthorized access to sensitive files, installation of malware, or creation of persistent backdoors on affected systems.
If Mitigated
Limited impact with proper network segmentation and endpoint protection blocking exploitation attempts.
🎯 Exploit Status
Requires network access to vulnerable Remote Desktop Client. No public exploit code available at this time.
🛠️ Fix & Mitigation
✅ Official Fix
Patch Version: To be determined from Microsoft's security update
Vendor Advisory: https://msrc.microsoft.com/update-guide/vulnerability/CVE-2025-26645
Restart Required: No
Instructions:
1. Apply Microsoft's security update for Remote Desktop Client when available. 2. Use Windows Update or Microsoft Update Catalog. 3. Verify installation through Windows Update history.
🔧 Temporary Workarounds
Disable Remote Desktop Services
WindowsTemporarily disable Remote Desktop services if not required
sc config TermService start= disabled
net stop TermService /y
Network Segmentation
WindowsRestrict network access to Remote Desktop services using firewall rules
netsh advfirewall firewall add rule name="Block RDP" dir=in protocol=TCP localport=3389 action=block
🧯 If You Can't Patch
- Implement strict network access controls to limit RDP connections to trusted sources only
- Deploy endpoint detection and response (EDR) solutions to monitor for exploitation attempts
🔍 How to Verify
Check if Vulnerable:
Check Remote Desktop Client version against Microsoft's security bulletin for affected versionsCheck Version:
mstsc /versionVerify Fix Applied:
Verify Windows Update history shows the security update for CVE-2025-26645 has been installed📡 Detection & Monitoring
Log Indicators:
- Unusual RDP connection attempts from unexpected sources
- Failed authentication attempts followed by successful connections
- Process creation events from RDP sessions
Network Indicators:
- Unusual RDP traffic patterns
- Connection attempts to RDP port 3389 from unauthorized IPs
- Anomalous network traffic following RDP connections
SIEM Query:
source="Windows Security" EventID=4625 AND LogonType=10 | stats count by src_ip