A21 Firmware
CVE-2026-2886
HIGH
Attack ChainAIDerived
Hypothetical attack flow derived from CVE metadata – not a confirmed exploit chain
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AccessAuthenticate to Tenda A21 device
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DeliverySend HTTP POST to /goform/SetOnlineDevName
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ExploitInject oversized devName parameter
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ExecutionTrigger stack buffer overflow
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ImpactExecute arbitrary code with device privileges
Vulnerability Assessment
| Weakness |
CWE
OWASP Top 10:2025
A06:2021 - Vulnerable and Outdated Components
ASVS 5.0
V15 - Secure Coding and Architecture Bounds checking, buffer size validation
MITRE ATT&CK
2 techniques across 2 tactics: Execution, Privilege Escalation The technique list with ATT&CK links and the kill-chain view is part of the Basic plan and up. |
| Exploitation Conditions | Tenda A21 firmware version 1.0.0.0, authenticated user account (PR:L requirement). Attack targets SetOnlineDevName function processing of devName parameter without bounds checking. Requires valid login credentials to remote web interface. |
| Impact | CVSS 8.8 (HIGH). Attack vector: Network. Complexity: Low. Privileges required: Low. User interaction: None. Exploitable via remote/network. Public exploit/POC available. |
| Exploit ScenarioDerived | A remote attacker could exploit this vulnerability to compromise the affected system. |
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Alert meAnalysisAIv1 – Mar 12, 2026
Stack Overflow and Tenda A21 1.0.0.0 are vulnerable to remote code execution through a stack-based buffer overflow in the device name configuration function, exploitable by authenticated attackers without user interaction. Public exploit code exists for this vulnerability, enabling attackers to achieve complete compromise of affected systems. No patch is currently available.
Earlier versions of this analysis (1)
A weakness has been identified in Tenda A21 1.0.0.0. This affects the function set_device_name of the file /goform/SetOnlineDevName. [CVSS 8.8 HIGH]
RemediationAI
Monitor vendor advisories for a patch. Enable ASLR, DEP/NX, and stack canaries where possible. Restrict network access to the affected service where possible.
Affects your stack
Find out whether the stacks and servers you run are on an affected version.
Checking this CVE against your own stacks and servers is part of the Basic plan and up.
Technical ContextAI · show details
Classified as CWE-119 (Buffer Overflow). Affects A21 Firmware. A weakness has been identified in Tenda A21 1.0.0.0. This affects the function set_device_name of the file /goform/SetOnlineDevName. This manipulation of the argument devName causes stack-based buffer overflow. It is possible to initiate the attack remotely. The exploit has been made available to the public and could be used for attacks.
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- Exploit and PoC references, threat intelligence from 22 sources
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Severity by source
AV:N/AC:L/PR:L/UI:N/S:U/C:H/I:H/A:H
Primary rating from NVD · only source for this CVE.
CVSS VectorNVD
Lifecycle Timeline
2DescriptionCVE.org
A weakness has been identified in Tenda A21 1.0.0.0. This affects the function set_device_name of the file /goform/SetOnlineDevName. This manipulation of the argument devName causes stack-based buffer overflow. It is possible to initiate the attack remotely. The exploit has been made available to the public and could be used for attacks.
Executive ViewAI
CVE-2026-2886 is a high-severity vulnerability affecting Tenda A21 wireless routers that could allow attackers to compromise device configuration and potentially gain unauthorized network access. Organizations using this equipment face immediate risk as public exploits exist and no patch is currently available from the vendor.
Restrict network access to the /goform/SetOnlineDevName endpoint using WAF or firewall rules; disable remote administration features if not operationally required; implement network segmentation to isolate affected routers from sensitive systems; enable enhanced logging and alerting on device configuration changes; consider replacing Tenda A21 units with alternative vendors pending patch availability.
Threat Intelligence Overview
NVD
CVE.org
EPSS
GitHub
VulDB
How this decision was reached
The engine reads each signal below and applies a fixed list of rules from top to bottom. The first rule that matches sets the recommended action – like a statement, every line is shown.
What every action level means
SSVC AssessmentENISA
Priority Score
Attack Technique
A buffer overflow occurs when a program writes more data to a memory buffer than it was allocated to hold, causing the excess data to spill into adjacent memory regions.
A stack-based buffer overflow occurs when a program writes more data to a buffer located on the stack than it was allocated to hold.
Affected Products (CPE)CVE.org
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