CVE-2025-65288
📋 TL;DR
A buffer overflow vulnerability in Mercury MR816v2 routers allows attackers to crash devices or potentially execute arbitrary code by sending crafted long hostnames. This affects LAN hosts that can communicate with the vulnerable router. The vulnerability stems from improper length validation when processing hostnames.
💻 Affected Systems
- Mercury MR816v2
📦 What is this software?
Mr816 Firmware by Mercurycom
⚠️ Risk & Real-World Impact
Worst Case
Remote code execution leading to complete device compromise, persistent backdoor installation, and lateral movement within the network.
Likely Case
Denial of service causing router crashes and network disruption, requiring manual reboots to restore functionality.
If Mitigated
Limited to denial of service with automatic recovery if device has watchdog timers, but still causes temporary network outages.
🎯 Exploit Status
Exploitation requires crafting specific hostname payloads and sending them to the router, but no public exploit code is available yet.
🛠️ Fix & Mitigation
✅ Official Fix
Patch Version: Unknown
Vendor Advisory: https://damiri.fr/en/cve/CVE-2025-65288
Restart Required: Yes
Instructions:
1. Check vendor website for firmware updates. 2. Download latest firmware if available. 3. Upload via router admin interface. 4. Reboot router after update.
🔧 Temporary Workarounds
Network Segmentation
allIsolate the vulnerable router from untrusted devices using VLANs or separate network segments
Hostname Length Restriction
allConfigure DHCP server to restrict hostname length for clients (if supported)
🧯 If You Can't Patch
- Replace affected router with updated model or different vendor
- Implement strict network access controls to limit which devices can communicate with the router
🔍 How to Verify
Check if Vulnerable:
Check router firmware version in admin interface: should show '4.8.7 Build 110427 Rel 36550n'Check Version:
Login to router admin interface and check System Status or Firmware Information pageVerify Fix Applied:
Verify firmware version has changed from vulnerable version after update📡 Detection & Monitoring
Log Indicators:
- Router crash/reboot logs
- Unusual hostname registration attempts
- Buffer overflow error messages in system logs
Network Indicators:
- Unusually long hostname in DHCP requests
- Router becoming unresponsive
- Multiple connection resets
SIEM Query:
source="router_logs" AND ("crash" OR "reboot" OR "buffer overflow")