CVE-2025-20736
📋 TL;DR
This vulnerability in MediaTek wlan AP driver allows local privilege escalation through an out-of-bounds write due to incorrect bounds checking. An attacker with System privilege can exploit this without user interaction to gain elevated privileges. This affects devices using MediaTek wireless chipsets with vulnerable driver versions.
💻 Affected Systems
- MediaTek wlan AP driver
📦 What is this software?
Openwrt by Openwrt
Openwrt by Openwrt
⚠️ Risk & Real-World Impact
Worst Case
Complete system compromise allowing attacker to execute arbitrary code with kernel privileges, potentially installing persistent malware or accessing all system resources.
Likely Case
Local privilege escalation from System to kernel-level access, enabling further system manipulation and persistence.
If Mitigated
Limited impact if proper privilege separation and driver sandboxing are implemented, though kernel access remains possible.
🎯 Exploit Status
Requires System privilege to exploit; kernel driver vulnerability with local access requirement.
🛠️ Fix & Mitigation
✅ Official Fix
Patch Version: Patch ID: WCNCR00435347
Vendor Advisory: https://corp.mediatek.com/product-security-bulletin/November-2025
Restart Required: Yes
Instructions:
1. Check device manufacturer for firmware updates
2. Apply MediaTek patch WCNCR00435347
3. Reboot device after patch installation
🔧 Temporary Workarounds
Restrict local access
allLimit physical and local network access to vulnerable devices
Disable unnecessary wireless features
linuxReduce attack surface by disabling unused wireless capabilities
🧯 If You Can't Patch
- Implement strict access controls to prevent unauthorized local access
- Monitor for suspicious privilege escalation attempts and kernel module loading
🔍 How to Verify
Check if Vulnerable:
Check driver version against MediaTek security bulletin; examine kernel logs for driver loadingCheck Version:
Check device firmware version in system settings or via manufacturer toolsVerify Fix Applied:
Verify patch WCNCR00435347 is applied through firmware version check📡 Detection & Monitoring
Log Indicators:
- Kernel panic logs
- Driver crash reports
- Unexpected privilege escalation events
Network Indicators:
- Local network scanning from device
- Unusual local traffic patterns
SIEM Query:
kernel: "wlan" AND ("panic" OR "oops" OR "segfault")