CVE-2026-3613
📋 TL;DR
A remote stack-based buffer overflow vulnerability in Wavlink WL-NU516U1 router's login.cgi component allows attackers to execute arbitrary code by manipulating the ipaddr parameter. This affects users of the vulnerable firmware version, potentially enabling complete device compromise. The exploit is publicly available, increasing the risk of widespread attacks.
💻 Affected Systems
- Wavlink WL-NU516U1
⚠️ Manual Verification Required
This CVE does not have specific version information in our database, so automatic vulnerability detection cannot determine if your system is affected.
Why? The CVE database entry doesn't specify which versions are vulnerable (no version ranges provided by the vendor/NVD).
🔒 Custom verification scripts are available for registered users. Sign up free to download automated test scripts.
- Review the CVE details at NVD
- Check vendor security advisories for your specific version
- Test if the vulnerability is exploitable in your environment
- Consider updating to the latest version as a precaution
⚠️ Risk & Real-World Impact
Worst Case
Remote code execution leading to full device compromise, persistent backdoor installation, network pivoting, and credential theft.
Likely Case
Device takeover enabling traffic interception, DNS manipulation, and botnet recruitment.
If Mitigated
Limited impact if device is behind strict firewall rules with no external access.
🎯 Exploit Status
Public GitHub repository contains detailed exploit code and analysis.
🛠️ Fix & Mitigation
✅ Official Fix
Patch Version: Unknown
Vendor Advisory: Unknown
Restart Required: Yes
Instructions:
1. Contact Wavlink support for patching information. 2. Monitor vendor website for firmware updates. 3. Apply any available firmware updates immediately.
🔧 Temporary Workarounds
Network Segmentation
allIsolate vulnerable device from internet and critical internal networks.
Access Control
linuxRestrict access to management interface using firewall rules.
iptables -A INPUT -p tcp --dport 80 -j DROP
iptables -A INPUT -p tcp --dport 443 -j DROP
🧯 If You Can't Patch
- Replace vulnerable device with secure alternative
- Implement strict network monitoring for exploitation attempts
🔍 How to Verify
Check if Vulnerable:
Check firmware version in web interface or via SSH: cat /etc/versionCheck Version:
cat /etc/version || grep -i version /proc/cmdlineVerify Fix Applied:
Verify firmware version has changed from V240425📡 Detection & Monitoring
Log Indicators:
- Unusual HTTP POST requests to /cgi-bin/login.cgi with long ipaddr parameters
- Multiple failed login attempts followed by buffer overflow patterns
Network Indicators:
- HTTP traffic to router management interface with malformed ipaddr parameters
- Unexpected outbound connections from router
SIEM Query:
source="router_logs" AND (url="/cgi-bin/login.cgi" AND ipaddr LENGTH > 100)