CVE-2021-27944
📋 TL;DR
This vulnerability allows unauthenticated attackers to execute arbitrary operating system commands on affected Vizio Smart TVs by exploiting insufficient access controls on high-privileged APIs. Attackers can upload malicious files to achieve remote code execution. Users of specific Vizio TV models with vulnerable firmware versions are affected.
💻 Affected Systems
- Vizio P65-F1 Smart TV
- Vizio E50x-E1 Smart TV
📦 What is this software?
⚠️ Risk & Real-World Impact
Worst Case
Complete compromise of the TV system allowing attackers to install persistent malware, access local network resources, spy on users via camera/microphone, or use the TV as a pivot point into the home network.
Likely Case
Attackers execute arbitrary commands to install cryptocurrency miners, botnet clients, or surveillance tools, potentially affecting TV performance and user privacy.
If Mitigated
With proper network segmentation and access controls, impact is limited to the TV device itself without lateral movement to other network devices.
🎯 Exploit Status
Exploit involves file upload to vulnerable APIs without authentication. Public technical details available from L9 Group advisory.
🛠️ Fix & Mitigation
✅ Official Fix
Patch Version: Later firmware versions than those listed
Vendor Advisory: https://www.vizio.com
Restart Required: Yes
Instructions:
1. Navigate to TV Settings > System > Check for Updates. 2. Install any available firmware updates. 3. Restart the TV after update completes.
🔧 Temporary Workarounds
Network Segmentation
allIsolate Smart TV on separate VLAN or guest network to prevent lateral movement
Disable Unused Services
allTurn off SmartCast features if not needed and disable remote management
🧯 If You Can't Patch
- Disconnect TV from internet and use only as display device
- Place TV behind firewall with strict inbound/outbound rules
🔍 How to Verify
Check if Vulnerable:
Check TV firmware version in Settings > System > System InformationCheck Version:
Not applicable - use TV settings menuVerify Fix Applied:
Confirm firmware version is newer than vulnerable versions listed📡 Detection & Monitoring
Log Indicators:
- Unusual file uploads to TV APIs
- Unexpected process execution
- Network connections to suspicious IPs
Network Indicators:
- HTTP POST requests to TV APIs with file uploads
- Unusual outbound connections from TV
SIEM Query:
source="tv_logs" AND (event="file_upload" OR event="api_access") AND user="unauthenticated"