CVE-2025-45841
📋 TL;DR
This vulnerability allows authenticated attackers to execute arbitrary code on TOTOLINK NR1800X routers by exploiting a stack overflow in the setSmsCfg function. Attackers with valid credentials can gain full control of affected devices. This affects TOTOLINK NR1800X routers running specific vulnerable firmware versions.
💻 Affected Systems
- TOTOLINK NR1800X
📦 What is this software?
⚠️ Risk & Real-World Impact
Worst Case
Complete device compromise leading to persistent backdoor installation, network traffic interception, lateral movement to other network devices, and participation in botnets.
Likely Case
Local attacker with valid credentials gains root access to the router, enabling configuration changes, credential theft, and network monitoring.
If Mitigated
With proper network segmentation and strong authentication, impact limited to isolated network segment with no critical assets.
🎯 Exploit Status
Exploit requires valid credentials but stack overflow exploitation is well-understood with public proof-of-concept available.
🛠️ Fix & Mitigation
✅ Official Fix
Patch Version: Unknown
Vendor Advisory: https://www.totolink.net/
Restart Required: Yes
Instructions:
1. Check vendor website for firmware updates. 2. Download latest firmware. 3. Log into router admin interface. 4. Navigate to firmware upgrade section. 5. Upload new firmware file. 6. Wait for reboot and verify version.
🔧 Temporary Workarounds
Disable SMS Configuration Interface
allRemove or restrict access to the vulnerable SMS configuration endpoint if possible through router configuration.
Network Segmentation
allIsolate affected routers in separate VLANs without access to critical internal resources.
🧯 If You Can't Patch
- Change all default credentials and implement strong password policies for router admin accounts
- Restrict router management interface access to specific trusted IP addresses only
🔍 How to Verify
Check if Vulnerable:
Check router firmware version via admin interface or SSH if enabled. Compare against vulnerable version V9.1.0u.6681_B20230703.Check Version:
Login to router web interface and check System Status or Firmware Information pageVerify Fix Applied:
Verify firmware version has been updated to a version newer than V9.1.0u.6681_B20230703.📡 Detection & Monitoring
Log Indicators:
- Unusual authentication attempts to router admin interface
- Multiple failed login attempts followed by successful login
- Unusual configuration changes to SMS settings
Network Indicators:
- Unusual outbound connections from router to unknown IP addresses
- Sudden changes in router network behavior or performance
SIEM Query:
source="router_logs" AND (event="authentication" AND result="success") AND user!="expected_admin" OR event="configuration_change" AND module="sms"