CVE-2025-9527
📋 TL;DR
A remote stack-based buffer overflow vulnerability exists in the Linksys E1700 router's QoS configuration function. Attackers can exploit this to execute arbitrary code or crash the device by sending specially crafted requests to the /goform/QoSSetup endpoint. This affects Linksys E1700 router users running firmware version 1.0.0.4.003.
💻 Affected Systems
- Linksys E1700
📦 What is this software?
⚠️ Risk & Real-World Impact
Worst Case
Remote code execution leading to complete device compromise, persistent backdoor installation, and lateral movement to connected networks.
Likely Case
Device crash causing denial of service, potential credential theft from router configuration, and network disruption.
If Mitigated
Limited to denial of service if exploit fails or device has memory protections, but still causes service interruption.
🎯 Exploit Status
Public proof-of-concept code exists on GitHub, making exploitation straightforward for attackers with basic skills.
🛠️ Fix & Mitigation
✅ Official Fix
Patch Version: Unknown
Vendor Advisory: None available
Restart Required: Yes
Instructions:
No official patch available. Contact Linksys support for firmware updates. If unavailable, consider replacing the device.
🔧 Temporary Workarounds
Disable QoS feature
allTurn off Quality of Service (QoS) functionality in router settings to remove the vulnerable endpoint.
Network segmentation
allIsolate the router on a separate network segment to limit attack surface.
🧯 If You Can't Patch
- Replace the router with a supported model from Linksys or another vendor
- Implement strict network access controls to limit traffic to the router's management interface
🔍 How to Verify
Check if Vulnerable:
Check router firmware version in web interface (typically under Administration or Status). If version is 1.0.0.4.003, device is vulnerable.Check Version:
Check via web interface at http://router_ip or use command: curl -s http://router_ip/status.cgi | grep firmwareVerify Fix Applied:
Verify firmware version has been updated to a version later than 1.0.0.4.003. No known fixed version exists currently.📡 Detection & Monitoring
Log Indicators:
- Multiple POST requests to /goform/QoSSetup with abnormal ack_policy parameter values
- Router crash/reboot logs
- Unusual outbound connections from router
Network Indicators:
- HTTP POST requests to /goform/QoSSetup with long or malformed ack_policy parameters
- Sudden increase in traffic to router management interface
SIEM Query:
source="router_logs" AND (url="/goform/QoSSetup" OR message="crash" OR message="reboot")