A21 Firmware
CVE-2026-2874
HIGH
Attack ChainAIDerived
Hypothetical attack flow derived from CVE metadata – not a confirmed exploit chain
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AccessAuthenticate to Tenda A21 web interface
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DeliverySend POST request to /goform/fast_setting_wifi_set
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ExploitInject oversized payload in ssid parameter
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ExecutionOverflow stack buffer
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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A06:2021 - Vulnerable and Outdated Components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 with web management interface accessible; attacker requires valid login credentials to access /goform/fast_setting_wifi_set endpoint |
| 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 stack-based buffer overflow. |
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Alert meAnalysisAIv1 – Mar 12, 2026
Remote code execution in Tenda A21 1.0.0.0 firmware via stack-based buffer overflow in the WiFi settings endpoint allows authenticated attackers to execute arbitrary code with full system privileges. The vulnerability exists in the fast_setting_wifi_set function where unsanitized SSID parameter input can overflow the stack, and public exploit code is currently available. No patch has been released for this high-severity vulnerability affecting both the A21 firmware and Stack Overflow products.
Earlier versions of this analysis (1)
A flaw has been found in Tenda A21 1.0.0.0. Impacted is the function form_fast_setting_wifi_set of the file /goform/fast_setting_wifi_set. [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 flaw has been found in Tenda A21 1.0.0.0. Impacted is the function form_fast_setting_wifi_set of the file /goform/fast_setting_wifi_set. Executing a manipulation of the argument ssid can lead to stack-based buffer overflow. It is possible to launch the attack remotely. The exploit has been published and may be used.
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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 flaw has been found in Tenda A21 1.0.0.0. Impacted is the function form_fast_setting_wifi_set of the file /goform/fast_setting_wifi_set. Executing a manipulation of the argument ssid can lead to stack-based buffer overflow. It is possible to launch the attack remotely. The exploit has been published and may be used.
Executive ViewAI
A high-severity vulnerability (CVE-2026-2874, CVSS 8.8) affects Tenda A21 wireless routers with active public exploits available. Organizations deploying these devices face immediate risk of unauthorized access and network compromise, potentially exposing sensitive data and business operations.
Disable the /goform/fast_setting_wifi_set endpoint at the network perimeter using WAF rules or firewall policies; restrict administrative access to affected devices through network segmentation and ACLs; disable remote management interfaces; implement continuous monitoring and logging of device configuration changes; consider deploying these devices only in isolated/guest networks with no access to critical systems until patching is available.
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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Exploit-DB