CVE-2021-22491
📋 TL;DR
This CVE describes an input validation vulnerability in Huawei smartphones that could allow attackers to disrupt service availability. Attackers could exploit improper input verification to cause denial of service conditions. The vulnerability affects Huawei smartphone users running vulnerable software versions.
💻 Affected Systems
- Huawei smartphones
📦 What is this software?
Emui by Huawei
Emui by Huawei
Magic Ui by Huawei
Magic Ui by Huawei
⚠️ Risk & Real-World Impact
Worst Case
Complete service disruption on affected smartphones, potentially rendering devices unusable until reboot or factory reset
Likely Case
Temporary service interruption affecting specific smartphone functions or applications
If Mitigated
Minimal impact with proper input validation and security controls in place
🎯 Exploit Status
CWE-20 indicates improper input validation; exploitation likely requires specific malformed input to trigger the vulnerability
🛠️ Fix & Mitigation
✅ Official Fix
Patch Version: Check Huawei security updates for specific patched versions
Vendor Advisory: https://consumer.huawei.com/en/support/bulletin/2021/7/
Restart Required: Yes
Instructions:
1. Check for security updates in device Settings > System & updates > Software update. 2. Download and install available security patches. 3. Restart device after installation completes.
🔧 Temporary Workarounds
Disable unnecessary services
allReduce attack surface by disabling non-essential smartphone services and features
Network segmentation
allRestrict smartphone network access to trusted networks only
🧯 If You Can't Patch
- Isolate affected devices from untrusted networks
- Implement strict input validation in any custom applications interacting with device services
🔍 How to Verify
Check if Vulnerable:
Check device security patch level in Settings > About phone > Build number and compare with Huawei security bulletinsCheck Version:
Settings > About phone > Build number (no CLI command available)Verify Fix Applied:
Verify security patch date is after July 2021 and matches patched versions in Huawei advisories📡 Detection & Monitoring
Log Indicators:
- Unexpected service crashes
- Abnormal input patterns in application logs
- System stability issues
Network Indicators:
- Unusual network traffic patterns to/from smartphone services
- Service disruption alerts
SIEM Query:
Device logs showing service interruptions or crashes following malformed input attempts