📄 Description (English)
A security flaw has been discovered in Tenda A21 1.0.0.0. Affected by this issue is the function set_qosMib_list of the file /goform/formSetQosBand. The manipulation of the argument list results in stack-based buffer overflow. The attack can be executed remotely. The exploit has been released to the public and may be used for attacks.
🤖 AI Executive Summary
A critical stack-based buffer overflow vulnerability exists in Tenda A21 router firmware version 1.0.0.0 affecting the QoS configuration function. With a CVSS score of 8.8 and publicly available exploits, this vulnerability allows remote attackers to execute arbitrary code without authentication. Immediate patching is essential for all affected devices, particularly those deployed in Saudi organizations.
📄 Description (Arabic)
🤖 AI Intelligence Analysis Analyzed: Apr 22, 2026 22:57
🇸🇦 Saudi Arabia Impact Assessment
This vulnerability poses significant risk to Saudi telecommunications providers (STC, Mobily, Zain) and ISPs using Tenda A21 routers in their infrastructure. Banking sector (SAMA-regulated institutions) faces risk if these routers are deployed in branch networks or customer-facing environments. Government agencies and critical infrastructure operators using these devices for network segmentation are at elevated risk. Small and medium enterprises across all sectors relying on Tenda equipment for network access are vulnerable to remote code execution, data exfiltration, and network compromise.
🏢 Affected Saudi Sectors
Telecommunications (STC, Mobily, Zain, ISPs)
Banking and Financial Services (SAMA-regulated)
Government and Public Administration
Critical Infrastructure and Energy
Healthcare
Small and Medium Enterprises
🎯 MITRE ATT&CK Techniques
⚖️ Saudi Risk Score (AI)
8.9
/ 10.0
🔧 Remediation Steps (English)
IMMEDIATE ACTIONS:
1. Identify all Tenda A21 devices running firmware 1.0.0.0 in your network using network scanning tools
2. Isolate affected devices from critical systems if immediate patching is not possible
3. Implement network-level access controls to restrict access to router management interfaces (ports 80, 443, 8080)
4. Monitor for suspicious QoS configuration requests to /goform/formSetQosBand endpoint
PATCHING GUIDANCE:
1. Download latest firmware from Tenda official website (verify digital signatures)
2. Apply firmware updates during maintenance windows
3. Reset router to factory defaults after firmware upgrade
4. Verify firmware version post-update using router admin interface
COMPENSATING CONTROLS (if patch unavailable):
1. Disable remote management access to router web interface
2. Implement firewall rules blocking external access to router management ports
3. Use VPN for any required remote router administration
4. Segment router management traffic on isolated VLAN
DETECTION RULES:
1. Monitor for POST requests to /goform/formSetQosBand with unusually large 'list' parameter values
2. Alert on any successful code execution attempts following QoS configuration changes
3. Track firmware version changes and unauthorized configuration modifications
4. Monitor router CPU/memory spikes correlating with QoS function calls
🔧 خطوات المعالجة (العربية)
الإجراءات الفورية:
1. تحديد جميع أجهزة Tenda A21 التي تعمل بالإصدار 1.0.0.0 في شبكتك باستخدام أدوات المسح
2. عزل الأجهزة المتأثرة عن الأنظمة الحرجة إذا لم يكن التحديث الفوري ممكنًا
3. تطبيق عناصر تحكم الوصول على مستوى الشبكة لتقييد الوصول إلى واجهات إدارة الموجه
4. مراقبة الطلبات المريبة لتكوين جودة الخدمة
إرشادات التصحيح:
1. تحميل أحدث إصدار من موقع Tenda الرسمي (التحقق من التوقيعات الرقمية)
2. تطبيق تحديثات البرامج الثابتة خلال نوافذ الصيانة
3. إعادة تعيين الموجه إلى إعدادات المصنع بعد التحديث
4. التحقق من إصدار البرنامج الثابت بعد التحديث
عناصر التحكم البديلة:
1. تعطيل الوصول البعيد إلى واجهة الويب للموجه
2. تطبيق قواعد جدار الحماية لحظر الوصول الخارجي
3. استخدام VPN لأي إدارة موجه بعيدة مطلوبة
4. فصل حركة إدارة الموجه على VLAN معزول
قواعد الكشف:
1. مراقبة طلبات POST إلى /goform/formSetQosBand بقيم معاملات كبيرة غير عادية
2. تنبيهات محاولات تنفيذ الأكواد بعد تغييرات تكوين جودة الخدمة
3. تتبع تغييرات إصدار البرنامج الثابت والتعديلات غير المصرح بها
4. مراقبة ارتفاع استخدام CPU/الذاكرة المرتبط باستدعاءات وظائف جودة الخدمة
📋 Regulatory Compliance Mapping
🟢 NCA ECC 2024
ECC 2024 A.12.6.1 - Management of technical vulnerabilities
ECC 2024 A.14.2.1 - Secure development policy
ECC 2024 A.12.2.1 - Monitoring and logging of network access
🔵 SAMA CSF
SAMA CSF ID.RA-1 - Asset Management and Vulnerability Management
SAMA CSF PR.IP-12 - Security patch management
SAMA CSF DE.CM-1 - Detection and monitoring of anomalous activity
🟡 ISO 27001:2022
ISO 27001:2022 A.12.2.1 - Monitoring and logging
ISO 27001:2022 A.12.6.1 - Management of technical vulnerabilities
ISO 27001:2022 A.14.2.1 - Secure development and change management
🟣 PCI DSS v4.0.1
PCI DSS 6.2 - Security patches must be installed within defined timeframe
PCI DSS 11.2 - Vulnerability scanning and remediation
🔗 References & Sources 5
🔗
https://github.com/QIU-DIE/cve-nneeww/issues/1
cna@vuldb.com
Exploit
Issue Tracking
Mitigation
Third Party Advisory
🔗
https://vuldb.com/?ctiid.347107
cna@vuldb.com
Permissions Required
VDB Entry
🔗
https://vuldb.com/?id.347107
cna@vuldb.com
Third Party Advisory
VDB Entry
🔗
https://vuldb.com/?submit.754627
cna@vuldb.com
Third Party Advisory
VDB Entry
🔗
https://www.tenda.com.cn/
cna@vuldb.com
Product
📦 Affected Products / CPE 1 entries
tenda:a21_firmware:1.0.0.0