CVE-2026-3715
📋 TL;DR
A stack-based buffer overflow vulnerability in the Wavlink WL-WN579X3-C router's firewall.cgi component allows remote attackers to execute arbitrary code by manipulating the del_flag argument. This affects users of Wavlink WL-WN579X3-C routers with firmware versions before 20260226. The vulnerability is remotely exploitable and a public exploit exists.
💻 Affected Systems
- Wavlink WL-WN579X3-C
📦 What is this software?
⚠️ Risk & Real-World Impact
Worst Case
Remote code execution leading to complete device compromise, network infiltration, and potential lateral movement to other systems.
Likely Case
Remote code execution allowing attackers to install malware, create backdoors, or use the device as a pivot point for further attacks.
If Mitigated
Limited impact if device is behind firewalls with strict ingress filtering and network segmentation.
🎯 Exploit Status
Exploit details are publicly available on GitHub. The vulnerability requires no authentication and has a straightforward exploitation path.
🛠️ Fix & Mitigation
✅ Official Fix
Patch Version: 20260226
Vendor Advisory: https://dl.wavlink.com/firmware/RD/WN579X3C_WAVLINK_V20260226_WO_cb3003b2.bin
Restart Required: Yes
Instructions:
1. Download firmware version 20260226 from Wavlink's website. 2. Log into router admin interface. 3. Navigate to firmware upgrade section. 4. Upload the new firmware file. 5. Wait for upgrade to complete and router to reboot.
🔧 Temporary Workarounds
Disable remote administration
allPrevent external access to the router's web interface
Navigate to router admin interface > Administration > Remote Management > Disable
Restrict access with firewall rules
linuxBlock external access to port 80/443 on the router
iptables -A INPUT -p tcp --dport 80 -j DROP
iptables -A INPUT -p tcp --dport 443 -j DROP
🧯 If You Can't Patch
- Isolate the router in a separate VLAN with strict access controls
- Implement network monitoring and intrusion detection for suspicious traffic to the router
🔍 How to Verify
Check if Vulnerable:
Check router firmware version in admin interface. If version is older than 20260226, device is vulnerable.Check Version:
curl -s http://router-ip/ | grep -i firmware || Check web interface manuallyVerify Fix Applied:
Confirm firmware version shows 20260226 or newer in router admin interface after upgrade.📡 Detection & Monitoring
Log Indicators:
- Unusual POST requests to /cgi-bin/firewall.cgi with manipulated parameters
- Multiple failed buffer overflow attempts in system logs
Network Indicators:
- Unusual traffic patterns to router web interface from external IPs
- POST requests to firewall.cgi with abnormal del_flag values
SIEM Query:
source="router_logs" AND (uri_path="/cgi-bin/firewall.cgi" AND (http_method="POST" AND (param="del_flag" AND length(value)>100)))