Hg9 Firmware
CVE-2026-2908
HIGH
Attack ChainAIDerived
Hypothetical attack flow derived from CVE metadata – not a confirmed exploit chain
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AccessAuthenticate to Tenda HG9 web interface
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DeliverySend POST request to /boaform/formLoopBack
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ExploitInject oversized Ethtype 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A06:2021 - Vulnerable and Outdated Components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 HG9 model 300001138 with Loopback Detection Configuration endpoint accessible at /boaform/formLoopBack. Attacker must have valid credentials to access web management interface (PR:L). Default or weak credentials increase exploitability. |
| 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 flaw, stack-based buffer overflow. |
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Alert meAnalysisAIv1 – Mar 12, 2026
Stack-based buffer overflow in Tenda HG9 firmware's loopback detection endpoint allows remote attackers with valid credentials to achieve complete system compromise through manipulation of the Ethtype parameter. Public exploit code exists for this vulnerability, creating immediate risk in deployed environments. No patch is currently available.
Earlier versions of this analysis (1)
A security vulnerability has been detected in Tenda HG9 300001138. Affected by this issue is some unknown functionality of the file /boaform/formLoopBack of the component Loopback Detection Configuration Endpoint. [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 Hg9 Firmware. A security vulnerability has been detected in Tenda HG9 300001138. Affected by this issue is some unknown functionality of the file /boaform/formLoopBack of the component Loopback Detection Configuration Endpoint. Such manipulation of the argument Ethtype leads to stack-based buffer overflow. The attack can be executed remotely. The exploit has been disclosed publicly 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 security vulnerability has been detected in Tenda HG9 300001138. Affected by this issue is some unknown functionality of the file /boaform/formLoopBack of the component Loopback Detection Configuration Endpoint. Such manipulation of the argument Ethtype leads to stack-based buffer overflow. The attack can be executed remotely. The exploit has been disclosed publicly and may be used.
Executive ViewAI
A high-severity vulnerability (CVE-2026-2908) affecting Tenda HG9 devices has been publicly disclosed with working exploits available, but no patch currently exists from the vendor. Organizations using this device model face immediate risk of unauthorized access and system compromise through the loopback detection configuration endpoint.
Implement network-level access controls restricting traffic to affected devices; deploy WAF/IDS rules to detect and block exploitation attempts targeting /boaform/formLoopBack; disable loopback detection feature if operationally feasible; segment affected devices to isolated VLANs with limited external connectivity; implement continuous monitoring for suspicious administrative access patterns; establish vendor communication channel for patch ETA updates.
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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