CVE-2025-20737
📋 TL;DR
This CVE describes a buffer overflow vulnerability in MediaTek's wlan AP driver where improper bounds checking allows out-of-bounds writes. An attacker with local user privileges can exploit this to escalate privileges without user interaction. This affects devices using MediaTek wireless chipsets with vulnerable driver versions.
💻 Affected Systems
- MediaTek wireless chipsets with wlan AP driver
📦 What is this software?
Openwrt by Openwrt
Openwrt by Openwrt
⚠️ Risk & Real-World Impact
Worst Case
Full system compromise with kernel-level code execution, allowing complete control over the affected device.
Likely Case
Local privilege escalation from user to root/admin privileges, enabling installation of malware, data theft, or persistence mechanisms.
If Mitigated
Limited impact if proper privilege separation and driver sandboxing are implemented, potentially containing the exploit to the driver context.
🎯 Exploit Status
Requires local access and user execution privileges; no public exploit code known at this time.
🛠️ Fix & Mitigation
✅ Official Fix
Patch Version: WCNCR00435343
Vendor Advisory: https://corp.mediatek.com/product-security-bulletin/November-2025
Restart Required: Yes
Instructions:
1. Check device manufacturer for firmware updates. 2. Apply the patch WCNCR00435343. 3. Reboot the device to load the updated driver.
🔧 Temporary Workarounds
Restrict local user access
allLimit local user accounts to reduce attack surface for privilege escalation.
Disable unnecessary wireless features
linuxTurn off Wi-Fi AP/hotspot functionality if not required.
nmcli radio wifi off
ip link set wlan0 down
🧯 If You Can't Patch
- Implement strict access controls to limit local user privileges
- Monitor for unusual privilege escalation attempts and driver crashes
🔍 How to Verify
Check if Vulnerable:
Check driver version against vendor advisory; look for 'wlan' driver version in system logs or driver files.Check Version:
dmesg | grep -i wlan OR check /sys/module/wlan/version if availableVerify Fix Applied:
Verify patch WCNCR00435343 is applied by checking driver version or system update status.📡 Detection & Monitoring
Log Indicators:
- Kernel panic messages
- Driver crash logs (wlan driver)
- Unexpected privilege escalation events
Network Indicators:
- Unusual local network traffic from device after privilege escalation
SIEM Query:
EventID=4624 AND PrivilegeList LIKE '%SeDebugPrivilege%' OR syslog contains 'wlan driver crash'