CVE-2025-20715
📋 TL;DR
This CVE describes an out-of-bounds write vulnerability in MediaTek's wlan AP driver due to incorrect bounds checking. It allows local privilege escalation from System to kernel-level access without user interaction. Affects devices using MediaTek Wi-Fi chipsets with vulnerable driver versions.
💻 Affected Systems
- MediaTek Wi-Fi chipsets with wlan AP driver
📦 What is this software?
Openwrt by Openwrt
Openwrt by Openwrt
⚠️ Risk & Real-World Impact
Worst Case
Complete system compromise with kernel-level code execution, allowing attackers to install persistent malware, steal sensitive data, or brick the device.
Likely Case
Local privilege escalation enabling attackers to bypass security controls, install additional malware, or gain persistence on compromised systems.
If Mitigated
Limited impact if proper kernel hardening, SELinux/apparmor policies, and driver signing enforcement are in place.
🎯 Exploit Status
Requires System privilege for initial access. Exploitation involves triggering the bounds check bypass to write beyond allocated memory in kernel space.
🛠️ Fix & Mitigation
✅ Official Fix
Patch Version: Driver patch WCNCR00421152
Vendor Advisory: https://corp.mediatek.com/product-security-bulletin/October-2025
Restart Required: Yes
Instructions:
1. Contact device manufacturer for firmware updates. 2. Apply MediaTek-provided driver patch WCNCR00421152. 3. Update device firmware through official channels. 4. Reboot device after update.
🔧 Temporary Workarounds
Disable vulnerable Wi-Fi functionality
androidTemporarily disable Wi-Fi AP/hotspot functionality if not required
Kernel hardening
linuxEnable kernel address space layout randomization (KASLR) and other memory protection features
echo 2 > /proc/sys/kernel/randomize_va_space
🧯 If You Can't Patch
- Implement strict access controls to prevent unauthorized users from obtaining System privilege
- Deploy endpoint detection and response (EDR) solutions to monitor for privilege escalation attempts
🔍 How to Verify
Check if Vulnerable:
Check driver version against MediaTek's advisory or contact device manufacturer for vulnerability statusCheck Version:
Check system logs or use manufacturer-specific tools to query Wi-Fi driver versionVerify Fix Applied:
Verify driver version has been updated to include patch WCNCR00421152📡 Detection & Monitoring
Log Indicators:
- Kernel panic logs
- Driver crash reports
- Unexpected privilege escalation events
Network Indicators:
- Unusual outbound connections from system processes
SIEM Query:
event_type:kernel AND (panic OR oops) AND wlan