CVE-2021-39973
📋 TL;DR
This CVE describes a null pointer dereference vulnerability in Huawei smartphones that could cause kernel crashes when exploited. It affects Huawei devices running HarmonyOS or EMUI. Successful exploitation requires local access to the device.
💻 Affected Systems
- Huawei smartphones
📦 What is this software?
Emui by Huawei
Harmonyos by Huawei
Magic Ui by Huawei
⚠️ Risk & Real-World Impact
Worst Case
Kernel panic leading to device crash and denial of service, potentially requiring physical restart of the smartphone.
Likely Case
Application crash or system instability when triggered by a malicious app with local access.
If Mitigated
No impact if patched or if exploit attempts are blocked by security controls.
🎯 Exploit Status
Requires local access and specific conditions to trigger the null pointer dereference. No public exploit code available.
🛠️ Fix & Mitigation
✅ Official Fix
Patch Version: HarmonyOS 2.0.0.230 and later, EMUI with November 2021 security patches
Vendor Advisory: https://consumer.huawei.com/en/support/bulletin/2021/11/
Restart Required: Yes
Instructions:
1. Check for system updates in device Settings. 2. Install available security updates. 3. Restart device after update completes.
🔧 Temporary Workarounds
Restrict app installations
allOnly install apps from trusted sources like official app stores to reduce risk of malicious apps exploiting this vulnerability.
Disable developer options
allEnsure developer options and USB debugging are disabled to prevent unauthorized local access.
🧯 If You Can't Patch
- Isolate affected devices from critical networks and limit user access
- Implement mobile device management (MDM) to control app installations and device settings
🔍 How to Verify
Check if Vulnerable:
Check device Settings > About phone > HarmonyOS/EMUI version. If version is before HarmonyOS 2.0.0.230 or before November 2021 security patches, device is vulnerable.Check Version:
Settings > About phone > HarmonyOS/EMUI versionVerify Fix Applied:
Verify device is running HarmonyOS 2.0.0.230 or later, or EMUI with November 2021 or later security patches.📡 Detection & Monitoring
Log Indicators:
- Kernel panic logs
- System crash reports
- Unexpected device reboots
Network Indicators:
- No network indicators - local vulnerability only
SIEM Query:
Device logs showing kernel panic or unexpected restart events on Huawei devices🔗 References
- https://consumer.huawei.com/en/support/bulletin/2021/11/
- https://device.harmonyos.com/en/docs/security/update/security-bulletins-202111-0000001217889667
- https://consumer.huawei.com/en/support/bulletin/2021/11/
- https://device.harmonyos.com/en/docs/security/update/security-bulletins-202111-0000001217889667
