CVE-2025-20734
📋 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. 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, install persistent malware, or bypass all security controls.
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 signing enforcement are in place, though kernel access remains possible.
🎯 Exploit Status
Requires System privilege to trigger, making exploitation dependent on initial access. No user interaction needed once privilege is obtained.
🛠️ Fix & Mitigation
✅ Official Fix
Patch Version: Patched in driver version with fix WCNCR00441507
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-provided driver patch WCNCR00441507. 3. Reboot device to load patched driver. 4. Verify patch installation through version checking.
🔧 Temporary Workarounds
Disable vulnerable driver module
linuxPrevent loading of the vulnerable wlan AP driver module
echo 'blacklist mtk_wlan_ap' >> /etc/modprobe.d/blacklist.conf
rmmod mtk_wlan_ap
Restrict System privilege access
allImplement strict access controls to limit who can obtain System privilege
🧯 If You Can't Patch
- Implement strict privilege separation and least privilege principles
- Monitor for unusual privilege escalation attempts and driver loading events
🔍 How to Verify
Check if Vulnerable:
Check driver version: lsmod | grep mtk_wlan_ap and compare with patched versionCheck Version:
modinfo mtk_wlan_ap | grep versionVerify Fix Applied:
Verify driver version contains patch WCNCR00441507 and test bounds checking functionality📡 Detection & Monitoring
Log Indicators:
- Kernel logs showing out-of-bounds memory writes
- Driver loading/unloading events
- Privilege escalation attempts
Network Indicators:
- None - local exploitation only
SIEM Query:
source="kernel" AND ("out of bounds" OR "bounds check" OR "mtk_wlan_ap")