CVE-2025-9253
📋 TL;DR
A stack-based buffer overflow vulnerability in Linksys range extenders allows remote attackers to execute arbitrary code by manipulating the ssidhex parameter. This affects multiple RE series models running vulnerable firmware versions. 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, lateral movement to internal networks, and persistent backdoor installation.
Likely Case
Device crash/reboot (DoS) or limited code execution to modify device settings and intercept network traffic.
If Mitigated
Limited impact if devices are behind firewalls with strict inbound filtering and network segmentation.
🎯 Exploit Status
Public exploit code exists on GitHub. The vulnerability requires no authentication and has straightforward exploitation due to buffer overflow in ssidhex parameter.
🛠️ Fix & Mitigation
✅ Official Fix
Patch Version: Unknown
Vendor Advisory: https://www.linksys.com/
Restart Required: Yes
Instructions:
1. Check Linksys website for firmware updates. 2. If update available, download and install via web interface. 3. Reboot device after update. Note: No official patch confirmed as vendor has not responded.
🔧 Temporary Workarounds
Network Segmentation
allIsolate range extenders on separate VLAN to limit attack surface
Access Control
linuxBlock external access to device management interfaces via 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 affected devices with non-vulnerable models or different brands
- Disable range extender functionality and use alternative networking solutions
🔍 How to Verify
Check if Vulnerable:
Access device web interface, check firmware version in Administration or Status section.Check Version:
curl -s http://device-ip/status.cgi | grep firmwareVerify Fix Applied:
Verify firmware version is no longer in affected version list. Test if /goform/RP_doSpecifySiteSurvey endpoint still accepts malformed ssidhex parameter.📡 Detection & Monitoring
Log Indicators:
- Multiple POST requests to /goform/RP_doSpecifySiteSurvey with long ssidhex parameters
- Device crash/reboot logs
Network Indicators:
- Unusual HTTP traffic to device management ports (80/443) with buffer overflow patterns
- Shellcode patterns in network traffic
SIEM Query:
source="firewall" AND dest_port=80 AND uri_path="/goform/RP_doSpecifySiteSurvey" AND content_length>1000