CVE-2025-20690
📋 TL;DR
This vulnerability in MediaTek wlan AP driver allows local attackers to read memory beyond intended boundaries, potentially exposing sensitive information. It affects devices with MediaTek Wi-Fi chipsets and requires local execution privileges but no user interaction. The risk is limited to information disclosure rather than system compromise.
💻 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
An attacker with local access could read sensitive kernel memory, potentially exposing cryptographic keys, passwords, or other protected data stored in adjacent memory regions.
Likely Case
Local information disclosure where an attacker can read some kernel memory contents, but the specific data exposed depends on memory layout and timing.
If Mitigated
With proper access controls limiting local user privileges, the impact is minimal as attackers cannot execute code to trigger the vulnerability.
🎯 Exploit Status
Requires local execution privileges and knowledge of memory layout. No user interaction needed once code is executed.
🛠️ Fix & Mitigation
✅ Official Fix
Patch Version: Patch ID: WCNCR00418038
Vendor Advisory: https://corp.mediatek.com/product-security-bulletin/July-2025
Restart Required: Yes
Instructions:
1. Check device manufacturer for firmware updates. 2. Apply MediaTek patch WCNCR00418038. 3. Update Wi-Fi driver/firmware. 4. Reboot device to load patched driver.
🔧 Temporary Workarounds
Restrict local user privileges
linuxLimit execution capabilities for local users to reduce attack surface
Use SELinux/AppArmor policies to restrict driver access
Implement least privilege principles for user accounts
🧯 If You Can't Patch
- Implement strict access controls to prevent unauthorized local code execution
- Monitor for suspicious local process activity and memory access patterns
🔍 How to Verify
Check if Vulnerable:
Check Wi-Fi driver version and compare against patched versions from device manufacturer. Look for MediaTek Wi-Fi chipset in device specifications.Check Version:
Check device-specific commands for Wi-Fi driver version (varies by device manufacturer)Verify Fix Applied:
Verify patch WCNCR00418038 is applied through device firmware version or driver version checks provided by manufacturer.📡 Detection & Monitoring
Log Indicators:
- Kernel logs showing out-of-bounds memory access
- Driver crash logs related to wlan AP driver
Network Indicators:
- No network indicators - this is a local vulnerability
SIEM Query:
Search for kernel panic logs containing 'wlan' or 'mediatek' driver references with memory access violations