CVE-2026-2085
📋 TL;DR
This CVE describes a command injection vulnerability in D-Link DWR-M921 routers via the USSD configuration endpoint. Attackers can execute arbitrary commands remotely by manipulating the ussdValue parameter. All users running affected firmware versions are vulnerable to potential system compromise.
💻 Affected Systems
- D-Link DWR-M921
📦 What is this software?
⚠️ Risk & Real-World Impact
Worst Case
Complete system takeover with root access, allowing attackers to install persistent malware, pivot to internal networks, or use the device for botnet activities.
Likely Case
Remote code execution leading to device compromise, credential theft, network reconnaissance, and potential lateral movement within the network.
If Mitigated
Limited impact with proper network segmentation, firewall rules blocking external access to management interfaces, and regular security monitoring.
🎯 Exploit Status
Public exploit details available on GitHub. Attack requires network access to the vulnerable endpoint but no authentication.
🛠️ Fix & Mitigation
✅ Official Fix
Patch Version: Unknown
Vendor Advisory: Not available
Restart Required: No
Instructions:
Check D-Link security advisories for firmware updates. If available, download from official D-Link support site and follow firmware upgrade procedures.
🔧 Temporary Workarounds
Block External Access to Management Interface
linuxConfigure firewall rules to block external access to router management interfaces (typically ports 80, 443, 8080).
iptables -A INPUT -p tcp --dport 80 -j DROP
iptables -A INPUT -p tcp --dport 443 -j DROP
iptables -A INPUT -p tcp --dport 8080 -j DROP
Disable USSD Configuration Endpoint
allIf possible, disable the vulnerable USSD configuration functionality through router settings.
🧯 If You Can't Patch
- Segment affected routers in isolated network zones with strict firewall rules
- Implement network monitoring for unusual outbound connections or command execution patterns
🔍 How to Verify
Check if Vulnerable:
Check router firmware version via web interface or SSH: cat /proc/version or check web admin panel system info.Check Version:
ssh admin@router-ip 'cat /proc/version' or check web interface at http://router-ip/system.htmlVerify Fix Applied:
Verify firmware version is updated beyond 1.1.50 and test USSD endpoint with controlled payloads.📡 Detection & Monitoring
Log Indicators:
- Unusual POST requests to /boafrm/formUSSDSetup
- Command execution patterns in system logs
- Failed authentication attempts to management interface
Network Indicators:
- Unexpected outbound connections from router
- Traffic to known malicious IPs
- Unusual port scanning from router
SIEM Query:
source="router-logs" AND (uri="/boafrm/formUSSDSetup" OR command="*;*" OR command="*|*")