CVE-2025-51087
📋 TL;DR
This vulnerability allows remote attackers to execute arbitrary code on Tenda AC8V4 routers by exploiting a stack-based buffer overflow in the saveParentControlInfo function. Attackers can trigger this by sending specially crafted requests to the vulnerable endpoint. Only users running the specific affected firmware version on Tenda AC8V4 routers are impacted.
💻 Affected Systems
- Tenda AC8V4
📦 What is this software?
⚠️ Risk & Real-World Impact
Worst Case
Complete device compromise leading to persistent remote code execution, router configuration modification, network traffic interception, and lateral movement to connected devices.
Likely Case
Router compromise allowing attackers to modify DNS settings, intercept traffic, deploy malware to connected devices, or create persistent backdoors.
If Mitigated
Denial of service or temporary disruption if exploit attempts are blocked by network controls, though device remains vulnerable.
🎯 Exploit Status
Public proof-of-concept code exists in GitHub repository, making exploitation straightforward for attackers with basic skills.
🛠️ Fix & Mitigation
✅ Official Fix
Patch Version: Unknown
Vendor Advisory: http://tenda.com
Restart Required: Yes
Instructions:
1. Check Tenda website for firmware updates. 2. Download latest firmware for AC8V4. 3. Access router admin interface. 4. Navigate to System Tools > Firmware Upgrade. 5. Upload and install new firmware. 6. Reboot router.
🔧 Temporary Workarounds
Disable remote management
allPrevent external access to router administration interface
Block vulnerable endpoint
linuxUse firewall rules to block access to /goform/saveParentControlInfo
iptables -A INPUT -p tcp --dport 80 -m string --string "/goform/saveParentControlInfo" --algo bm -j DROP
🧯 If You Can't Patch
- Isolate router on separate VLAN with strict firewall rules
- Implement network monitoring for exploit attempts and unusual traffic patterns
🔍 How to Verify
Check if Vulnerable:
Access router web interface, navigate to System Status, check firmware version matches V16.03.34.06Check Version:
curl -s http://router-ip/goform/getStatus | grep versionVerify Fix Applied:
After firmware update, verify version is different from V16.03.34.06 and test if /goform/saveParentControlInfo endpoint behaves differently📡 Detection & Monitoring
Log Indicators:
- Multiple POST requests to /goform/saveParentControlInfo with long time parameter values
- Router crash/reboot logs
- Unusual configuration changes
Network Indicators:
- HTTP POST requests to router IP on port 80 with long strings in time parameter
- Sudden traffic pattern changes after exploit
SIEM Query:
source="router.log" AND (url="/goform/saveParentControlInfo" AND content_length>100)