CVE-2025-8817
📋 TL;DR
A stack-based buffer overflow vulnerability in Linksys WiFi range extenders allows remote attackers to execute arbitrary code by manipulating the lan2enabled parameter. This affects Linksys RE6250, RE6300, RE6350, RE6500, RE7000, and RE9000 devices with firmware up to August 1, 2025. Attackers can exploit this without authentication to potentially take full control of affected devices.
💻 Affected Systems
- Linksys RE6250
- Linksys RE6300
- Linksys RE6350
- Linksys RE6500
- Linksys RE7000
- Linksys RE9000
📦 What is this software?
⚠️ Risk & Real-World Impact
Worst Case
Remote code execution leading to complete device compromise, creation of persistent backdoors, lateral movement to other network devices, and data exfiltration.
Likely Case
Device takeover enabling network traffic interception, DNS hijacking, credential theft, and participation in botnets.
If Mitigated
Limited impact if devices are isolated on separate VLANs with strict network segmentation and egress filtering.
🎯 Exploit Status
Public proof-of-concept available on GitHub. Exploitation requires sending crafted HTTP POST request to /goform/setLan endpoint.
🛠️ Fix & Mitigation
✅ Official Fix
Patch Version: Unknown
Vendor Advisory: None available
Restart Required: Yes
Instructions:
1. Check Linksys support website for firmware updates. 2. Download latest firmware for your model. 3. Access device web interface. 4. Navigate to firmware update section. 5. Upload and apply new firmware. 6. Reboot device.
🔧 Temporary Workarounds
Disable web management interface
allTurn off remote management to prevent external exploitation
Access device web interface -> Administration -> Management -> Disable Remote Management
Network segmentation
linuxIsolate range extenders on separate VLAN with restricted access
# Example firewall rule to restrict access to device management IP
# iptables -A INPUT -s 192.168.1.0/24 -d [DEVICE_IP] -p tcp --dport 80 -j ACCEPT
# iptables -A INPUT -d [DEVICE_IP] -p tcp --dport 80 -j DROP
🧯 If You Can't Patch
- Replace vulnerable devices with different models or brands
- Implement strict network access controls allowing only trusted IPs to communicate with device management interface
🔍 How to Verify
Check if Vulnerable:
Check firmware version in device web interface under Administration -> Firmware Upgrade. If version date is 20250801 or earlier, device is vulnerable.Check Version:
curl -s http://[device_ip]/goform/getSysInfo | grep firmware_versionVerify Fix Applied:
Verify firmware version shows date after 20250801. Test by attempting to access /goform/setLan endpoint with proper authentication.📡 Detection & Monitoring
Log Indicators:
- Multiple POST requests to /goform/setLan with unusual lan2enabled parameter values
- Device reboot logs following suspicious web requests
- Unusual outbound connections from range extender
Network Indicators:
- HTTP POST requests to /goform/setLan with long lan2enabled parameter
- Unusual traffic patterns from range extender to external IPs
- DNS queries to suspicious domains from device
SIEM Query:
source="firewall" AND dest_port=80 AND uri_path="/goform/setLan" AND method="POST" AND content_length>100🔗 References
- https://github.com/wudipjq/my_vuln/blob/main/Linksys1/vuln_51/51.md
- https://github.com/wudipjq/my_vuln/blob/main/Linksys1/vuln_51/51.md#poc
- https://vuldb.com/?ctiid.319351
- https://vuldb.com/?id.319351
- https://vuldb.com/?submit.626681
- https://www.linksys.com/
- https://github.com/wudipjq/my_vuln/blob/main/Linksys1/vuln_51/51.md
- https://github.com/wudipjq/my_vuln/blob/main/Linksys1/vuln_51/51.md#poc
