CVE-2026-20418

9.8 CRITICAL
Remote Code Execution

📋 TL;DR

CVE-2026-20418 is a critical out-of-bounds write vulnerability in Thread protocol implementations that allows remote attackers to execute arbitrary code without authentication or user interaction. This affects devices using vulnerable MediaTek Thread implementations, primarily IoT and networking equipment. Successful exploitation could lead to complete system compromise.

💻 Affected Systems

Products:
  • MediaTek Thread implementations
  • IoT devices with MediaTek chipsets
  • Network equipment using affected Thread stacks
Versions: All versions prior to patch WCNCR00465153
Operating Systems: Embedded RTOS, Linux-based IoT systems
Default Config Vulnerable: ⚠️ Yes
Notes: Affects devices with Thread networking enabled; exact product list requires vendor disclosure

⚠️ Risk & Real-World Impact

🔴

Worst Case

Remote attacker gains full system control, installs persistent malware, pivots to internal networks, and creates botnet nodes for further attacks.

🟠

Likely Case

Remote code execution leading to device takeover, data theft, and lateral movement within IoT/network environments.

🟢

If Mitigated

With proper network segmentation and monitoring, impact limited to isolated network segments with containment possible.

🌐 Internet-Facing: HIGH
🏢 Internal Only: MEDIUM

🎯 Exploit Status

Public PoC: ✅ No
Weaponized: UNKNOWN
Unauthenticated Exploit: ⚠️ Yes
Complexity: LOW

No authentication required; remote exploitation possible via Thread network packets

🛠️ Fix & Mitigation

✅ Official Fix

Patch Version: Patch ID: WCNCR00465153

Vendor Advisory: https://corp.mediatek.com/product-security-bulletin/February-2026

Restart Required: Yes

Instructions:

1. Contact device manufacturer for firmware updates 2. Apply patch WCNCR00465153 3. Reboot affected devices 4. Verify patch installation

🔧 Temporary Workarounds

Network Segmentation

all

Isolate Thread networks from critical infrastructure

Disable Thread if Unused

linux

Turn off Thread networking on non-essential devices

systemctl disable thread-service
modprobe -r thread_module

🧯 If You Can't Patch

  • Implement strict network ACLs to block unauthorized Thread traffic
  • Deploy intrusion detection systems monitoring for Thread protocol anomalies

🔍 How to Verify

Check if Vulnerable:

Check device firmware version against vendor advisory; examine Thread service status

Check Version:

cat /proc/version | grep -i mediatek || dmesg | grep -i thread

Verify Fix Applied:

Verify patch WCNCR00465153 is installed; test Thread functionality remains operational

📡 Detection & Monitoring

Log Indicators:

  • Thread service crashes
  • Memory access violations in system logs
  • Unexpected process spawning

Network Indicators:

  • Malformed Thread protocol packets
  • Unusual Thread network traffic patterns

SIEM Query:

source="thread.log" AND (error OR crash OR "out of bounds")

📊 Metadata

CVE ID: CVE-2026-20418
CVSS v3 Score: 9.8 (CRITICAL)
CVSS Vector: CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:H/I:H/A:H
CWE: CWE-787
Published: February 2, 2026
Last Updated: February 4, 2026

🤖 AI-assisted analysis, reviewed for accuracy

🔗 References

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