CVE-2025-55972
📋 TL;DR
This vulnerability allows remote attackers to cause a Denial of Service (DoS) on TCL Smart TVs by flooding the UPnP/DLNA MediaRenderer with malformed SetAVTransportURI requests. The TV becomes completely unresponsive during the attack, affecting all operations including manual controls and reboots. All TCL Smart TVs with the vulnerable UPnP implementation are affected.
💻 Affected Systems
- TCL Smart TVs
📦 What is this software?
⚠️ Risk & Real-World Impact
Worst Case
Complete TV unavailability for extended periods, disrupting all functionality including emergency alerts, streaming services, and basic TV operations until attack stops.
Likely Case
Temporary TV unresponsiveness during targeted attacks, requiring network isolation or waiting for attack to cease.
If Mitigated
Minimal impact with proper network segmentation and UPnP disabled.
🎯 Exploit Status
Simple Python scripts available on GitHub demonstrate the attack. No authentication required.
🛠️ Fix & Mitigation
✅ Official Fix
Patch Version: Not available
Vendor Advisory: Not available
Restart Required: No
Instructions:
No official patch available. Check TCL support website for firmware updates and apply if available.
🔧 Temporary Workarounds
Disable UPnP/DLNA MediaRenderer
allTurn off UPnP/DLNA functionality in TV settings to prevent exploitation.
Network Segmentation
allIsolate TV on separate VLAN or network segment away from untrusted devices.
🧯 If You Can't Patch
- Disconnect TV from network when not in use
- Implement network firewall rules to block UPnP traffic (port 1900/udp and related TCP ports) to TV
🔍 How to Verify
Check if Vulnerable:
Check if UPnP/DLNA MediaRenderer is enabled in TV settings. If enabled and TV is on network, it's vulnerable.Check Version:
Check TV firmware version in Settings > System > AboutVerify Fix Applied:
Test by attempting to access UPnP services on TV port 1900/udp. If disabled or blocked, fix is applied.📡 Detection & Monitoring
Log Indicators:
- High volume of malformed SOAP requests to UPnP endpoint
- TV system logs showing service crashes
Network Indicators:
- Flood of SetAVTransportURI requests to TV on UPnP ports
- Abnormal traffic patterns to port 1900/udp
SIEM Query:
source_ip:* dest_port:1900 protocol:udp packet_count > 1000 within 1m