CVE-2025-50755
📋 TL;DR
This vulnerability allows attackers to execute arbitrary commands on Wavlink WN535K3 routers by sending specially crafted requests to the set_sys_cmd function. Attackers can potentially take full control of affected devices, install malware, or pivot to other network systems. Only users of specific Wavlink router models with vulnerable firmware are affected.
💻 Affected Systems
- Wavlink WN535K3
📦 What is this software?
⚠️ Risk & Real-World Impact
Worst Case
Complete device compromise leading to persistent backdoor installation, network pivoting to internal systems, data exfiltration, and use in botnets or ransomware attacks.
Likely Case
Router compromise allowing traffic interception, DNS hijacking, credential theft, and use as a foothold for further network attacks.
If Mitigated
Limited impact if device is behind firewall with strict inbound rules, has network segmentation, and regular monitoring for suspicious activity.
🎯 Exploit Status
Proof of concept available in GitHub repository. Exploitation requires sending crafted HTTP requests to the vulnerable endpoint.
🛠️ Fix & Mitigation
✅ Official Fix
Patch Version: Check Wavlink support for updated firmware
Vendor Advisory: Not publicly available - contact Wavlink support
Restart Required: Yes
Instructions:
1. Contact Wavlink support for latest firmware. 2. Download firmware update. 3. Access router admin interface. 4. Navigate to firmware update section. 5. Upload and apply new firmware. 6. Reboot router.
🔧 Temporary Workarounds
Network Access Restriction
allBlock external access to router admin interface using firewall rules
Disable Remote Management
allTurn off remote administration features in router settings
🧯 If You Can't Patch
- Isolate router on separate VLAN with strict firewall rules
- Implement network monitoring for suspicious HTTP requests to router admin interface
🔍 How to Verify
Check if Vulnerable:
Check router firmware version in admin interface under System Status or Firmware Update sectionCheck Version:
Check via router web interface or SSH if enabled: cat /proc/version or similar firmware version fileVerify Fix Applied:
Verify firmware version has been updated to a version later than 20191010📡 Detection & Monitoring
Log Indicators:
- Unusual HTTP POST requests to router admin endpoints
- Commands containing shell metacharacters in request parameters
- Multiple failed authentication attempts followed by successful command execution
Network Indicators:
- HTTP traffic to router on admin ports from unexpected sources
- Outbound connections from router to suspicious IPs
- Unusual DNS queries from router
SIEM Query:
source="router_logs" AND (uri="*set_sys_cmd*" OR command="*;*" OR command="*|*" OR command="*`*" OR command="*$(*")