CVE-2026-2155
📋 TL;DR
This CVE describes a remote command injection vulnerability in D-Link DIR-823X routers. Attackers can execute arbitrary operating system commands by manipulating the dmz_host/dmz_enable parameters in the configuration handler. All users of affected D-Link DIR-823X routers with vulnerable firmware are at risk.
💻 Affected Systems
- D-Link DIR-823X
📦 What is this software?
⚠️ Risk & Real-World Impact
Worst Case
Complete device compromise allowing attackers to install persistent backdoors, pivot to internal networks, intercept traffic, or brick the device.
Likely Case
Attackers gain shell access to execute commands, potentially stealing credentials, modifying configurations, or using the device as a botnet node.
If Mitigated
Limited impact if device is behind strict firewall rules, though command injection could still be exploited if accessible.
🎯 Exploit Status
Exploit details are publicly available on GitHub, making this easily weaponizable by attackers.
🛠️ Fix & Mitigation
✅ Official Fix
Patch Version: Unknown
Vendor Advisory: Not available
Restart Required: No
Instructions:
Check D-Link's official security advisories page for firmware updates. If available, download and install the latest firmware through the router's web interface.
🔧 Temporary Workarounds
Disable Remote Management
allPrevent external access to the vulnerable web interface
Access router web interface > Advanced > Remote Management > Disable
Block Access to Vulnerable Endpoint
linuxUse firewall rules to block access to the vulnerable /goform/set_dmz endpoint
iptables -A INPUT -p tcp --dport 80 -m string --string "/goform/set_dmz" --algo bm -j DROP
iptables -A INPUT -p tcp --dport 443 -m string --string "/goform/set_dmz" --algo bm -j DROP
🧯 If You Can't Patch
- Replace affected D-Link DIR-823X routers with different models or brands that are not vulnerable
- Isolate vulnerable routers in a separate network segment with strict firewall rules limiting communication
🔍 How to Verify
Check if Vulnerable:
Check firmware version in router web interface (Status > Device Info). If version is 250416, device is vulnerable.Check Version:
curl -s http://router-ip/status.asp | grep -i firmwareVerify Fix Applied:
After firmware update, verify version has changed from 250416 to a newer version.📡 Detection & Monitoring
Log Indicators:
- Unusual POST requests to /goform/set_dmz with shell metacharacters in parameters
- Unexpected command execution in system logs
Network Indicators:
- HTTP requests containing shell commands (semicolons, pipes, backticks) in dmz_host/dmz_enable parameters
- Outbound connections from router to suspicious IPs
SIEM Query:
source="router_logs" AND uri_path="/goform/set_dmz" AND (dmz_host="*;*" OR dmz_enable="*`*" OR dmz_host="*|*")