CVE-2025-20717
📋 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 to gain higher privileges without user interaction. This affects devices using MediaTek wireless chipsets.
💻 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 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; kernel driver exploitation requires specific knowledge of driver internals
🛠️ Fix & Mitigation
✅ Official Fix
Patch Version: Patch ID: WCNCR00419946
Vendor Advisory: https://corp.mediatek.com/product-security-bulletin/October-2025
Restart Required: Yes
Instructions:
1. Check device manufacturer for firmware updates. 2. Apply MediaTek-provided patch WCNCR00419946. 3. Reboot device to load patched driver.
🔧 Temporary Workarounds
Disable vulnerable driver module
linuxUnload or blacklist the vulnerable wlan AP driver module
rmmod mt_wlan_ap
echo 'blacklist mt_wlan_ap' >> /etc/modprobe.d/blacklist.conf
Restrict driver permissions
linuxSet strict file permissions on driver module to limit access
chmod 600 /lib/modules/$(uname -r)/kernel/drivers/net/wireless/mediatek/mt_wlan_ap.ko
🧯 If You Can't Patch
- Implement strict privilege separation to limit System account access
- Monitor for suspicious driver-related activity and privilege escalation attempts
🔍 How to Verify
Check if Vulnerable:
Check driver version: lsmod | grep mt_wlan_ap and compare against patched versionsCheck Version:
modinfo mt_wlan_ap | grep versionVerify Fix Applied:
Verify patch application: dmesg | grep WCNCR00419946 or check driver version after update📡 Detection & Monitoring
Log Indicators:
- Kernel logs showing out-of-bounds memory access
- Driver crash logs
- Unexpected privilege escalation events
Network Indicators:
- Unusual wireless driver behavior
SIEM Query:
source="kernel" AND ("out of bounds" OR "bounds check" OR "mt_wlan_ap")