CVE-2025-20684
📋 TL;DR
This CVE describes a critical out-of-bounds write vulnerability in MediaTek's WLAN AP driver. An attacker with local user privileges can exploit this to gain kernel-level system access without user interaction. This affects devices using MediaTek Wi-Fi chipsets.
💻 Affected Systems
- MediaTek WLAN AP driver
📦 What is this software?
⚠️ Risk & Real-World Impact
Worst Case
Full system compromise with kernel-level code execution, allowing complete control over the device, data theft, and persistence.
Likely Case
Local privilege escalation to root/system privileges, enabling installation of malware, credential theft, and lateral movement.
If Mitigated
Limited impact if proper kernel hardening, exploit mitigations, and least privilege principles are implemented.
🎯 Exploit Status
Requires local user access but no user interaction. Kernel exploitation requires bypassing modern mitigations like KASLR, SMAP, SMEP.
🛠️ Fix & Mitigation
✅ Official Fix
Patch Version: Patch ID: WCNCR00416939
Vendor Advisory: https://corp.mediatek.com/product-security-bulletin/July-2025
Restart Required: Yes
Instructions:
1. Check device manufacturer for firmware updates. 2. Apply MediaTek-provided patch WCNCR00416939. 3. Reboot device to load patched driver.
🔧 Temporary Workarounds
Disable vulnerable Wi-Fi interface
linuxTemporarily disable the affected MediaTek Wi-Fi interface to prevent exploitation.
sudo ifconfig wlan0 down
sudo ip link set wlan0 down
Restrict local user access
allLimit local user accounts and implement strict access controls to reduce attack surface.
🧯 If You Can't Patch
- Implement strict network segmentation to isolate vulnerable devices.
- Deploy endpoint detection and response (EDR) solutions to monitor for privilege escalation attempts.
🔍 How to Verify
Check if Vulnerable:
Check Wi-Fi driver version: 'lsmod | grep mtk' or 'dmesg | grep -i mediatek'. Compare with vendor advisory.Check Version:
uname -r (kernel version) and check Wi-Fi driver details in /sys/module/Verify Fix Applied:
Verify patch application via system logs or driver version check. Ensure patch ID WCNCR00416939 is applied.📡 Detection & Monitoring
Log Indicators:
- Kernel panic logs
- Driver crash messages in dmesg
- Unexpected privilege escalation events
Network Indicators:
- Unusual local network traffic from compromised hosts
SIEM Query:
EventID=4688 AND ProcessName LIKE '%wlan%' AND NewIntegrityLevel=System