CVE-2025-20741
📋 TL;DR
This CVE describes an out-of-bounds write vulnerability in MediaTek wlan AP drivers that could allow local privilege escalation. Attackers with initial System privilege access could exploit this to gain higher privileges without user interaction. This affects devices using vulnerable MediaTek wireless chipset drivers.
💻 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 attackers to execute arbitrary code with kernel privileges, potentially installing persistent malware or accessing sensitive data.
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 existing System privilege access, making initial access barrier significant. No public exploit code identified.
🛠️ Fix & Mitigation
✅ Official Fix
Patch Version: Patch ID: WCNCR00434422
Vendor Advisory: https://corp.mediatek.com/product-security-bulletin/November-2025
Restart Required: Yes
Instructions:
1. Check device manufacturer for firmware updates containing patch WCNCR00434422. 2. Apply manufacturer-provided firmware update. 3. Reboot device to load patched driver.
🔧 Temporary Workarounds
Disable vulnerable driver module
linuxPrevent loading of the vulnerable wlan AP driver module if not required
echo 'blacklist mtk_wlan_ap' >> /etc/modprobe.d/blacklist.conf
rmmod mtk_wlan_ap
🧯 If You Can't Patch
- Implement strict privilege separation to limit System privilege access
- Monitor for unusual privilege escalation attempts and driver loading events
🔍 How to Verify
Check if Vulnerable:
Check driver version and compare against patched versions from manufacturer. Look for driver modules related to MediaTek wlan AP.Check Version:
modinfo mtk_wlan_ap | grep version (Linux) or check firmware version in device settingsVerify Fix Applied:
Verify patch WCNCR00434422 is applied in firmware version and driver module version shows updated.📡 Detection & Monitoring
Log Indicators:
- Kernel logs showing driver crashes or out-of-bounds memory access
- Unexpected privilege escalation events from System to kernel
Network Indicators:
- None - local exploitation only
SIEM Query:
source="kernel" AND ("out of bounds" OR "OOB" OR "mtk_wlan")