CVE-2021-22391
📋 TL;DR
This vulnerability in Huawei smartphones involves an incorrect buffer size calculation that could allow attackers to trigger a system reset. It affects specific Huawei smartphone models running vulnerable software versions. Exploitation requires local access to the device.
💻 Affected Systems
- Huawei smartphones
📦 What is this software?
Emui by Huawei
Emui by Huawei
Emui by Huawei
Emui by Huawei
Emui by Huawei
Emui by Huawei
Magic Ui by Huawei
Magic Ui by Huawei
Magic Ui by Huawei
Magic Ui by Huawei
Magic Ui by Huawei
⚠️ Risk & Real-World Impact
Worst Case
Persistent denial of service through repeated system resets, potentially causing data loss or corruption.
Likely Case
Temporary denial of service through system reset when triggered by malicious local applications.
If Mitigated
No impact if device is patched or proper application sandboxing prevents exploitation.
🎯 Exploit Status
Requires local application execution with sufficient permissions to trigger the buffer calculation error.
🛠️ Fix & Mitigation
✅ Official Fix
Patch Version: Security update versions released in June 2021
Vendor Advisory: https://consumer.huawei.com/en/support/bulletin/2021/6/
Restart Required: Yes
Instructions:
1. Check for system updates in Settings > System & updates > Software update. 2. Install available security updates. 3. Restart device after installation.
🔧 Temporary Workarounds
Restrict application installations
allOnly install applications from trusted sources like Huawei AppGallery
Disable unknown sources
allPrevent installation of applications from unknown sources
🧯 If You Can't Patch
- Monitor device for unexpected resets or instability
- Limit device usage to essential functions and avoid untrusted applications
🔍 How to Verify
Check if Vulnerable:
Check device version in Settings > About phone > Build number and compare against Huawei's June 2021 security bulletinCheck Version:
Settings > About phone > Build numberVerify Fix Applied:
Verify security patch level in Settings > About phone > Build number shows June 2021 or later security updates📡 Detection & Monitoring
Log Indicators:
- Unexpected system resets
- Kernel panic or crash logs
- Application permission violations
Network Indicators:
- No network indicators - local vulnerability
SIEM Query:
Device logs showing repeated unexpected reboots or system crashes