External risk intelligence

Tenda i29 Buffer Overflow in lanCfgSet

CVE advisorySeverity: CRITICAL (CVSS 9.8)

CVE-2023-50985

The vulnerability affects a LAN configuration setting in a Tenda wireless access point. While network-reachable, this functionality is typically restricted to local administrative access within the internal network rather than being exposed to the public internet in standard deployment patterns.

Out-of-bounds Write

Tenda I29 Firmware

1.0.0.21.0.0.5

Halo Surface Signal: 2 out of 5 — less likely to be public-facing.

External exposure likelihood

Horizon Alert

Summary of the vulnerability and why it matters

This advisory details a critical security flaw in Tenda i29 devices that allows unauthorized access and control over the network. The vulnerability, a buffer overflow, could potentially enable attackers to compromise the device's configuration and impact its operations. The main concern is confirming relevance and exposure.

Flaw lets attackers control network devices.
Critical flaw needs executive awareness.
Confirm if this affects your environment.

Attack Path

How an attacker could exploit the issue

An attacker could reach this vulnerability by sending a specially crafted network request. This request would target the device's local network configuration function, specifically the `lanCfgSet` operation. If successful, this could lead to a buffer overflow, potentially allowing the attacker to take control of the device.

Requires network access.
Exploits a network configuration setting.
Could lead to full device compromise.

Live Threat

Current exploitation, exposure, and threat context

This vulnerability could allow an unauthenticated attacker to overwrite memory in the device's firmware, potentially leading to a denial of service or allowing for arbitrary code execution when accessed via the network. The specific impact depends on how the `lanGw` parameter is handled and the device's configuration.

Device firmware integrity.
Network-based buffer overflow.
Unspecified impact on service.

Operational Fix

Recommended remediation, mitigation, and detection steps

This vulnerability in Tenda i29 firmware, specifically a buffer overflow in the `lanCfgSet` function, is likely to be managed by the infrastructure or network security teams responsible for managing network appliances. The first critical step is to identify all deployed Tenda i29 devices, determine their network exposure, and confirm their business criticality. Following this, the accountable owner should be identified to plan remediation based on the assessed risk.

Infrastructure or network security teams own this.
Verify device presence and network exposure.
Plan remediation based on assessed risk.

Supplementary metadata

CVSS vector

Validate whether this threat affects your internet-facing exposure.

Halo Threat Intelligence helps prioritize remediation with Halo Surface Signal and H/A/L/O context. Start exposure validation with a free external attack surface trial.

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Frequently asked questions

What is the Tenda i29 device?

The Tenda i29 is a wireless access point designed to provide network connectivity. It runs firmware that manages various network settings, including the gateway configuration. In this context, it acts as a network infrastructure component that connects devices to a local area network.

What is the buffer overflow vulnerability in CVE-2023-50985?

This is a memory-related weakness classified as CWE-787. It occurs when a program writes more data to a memory buffer than it can hold, overwriting adjacent memory. In this CVE, the flaw exists in the lanCfgSet function, which improperly handles input provided through the lanGw parameter, potentially allowing unauthorized memory manipulation.

How is this vulnerability triggered?

An attacker triggers this by sending a specially crafted network request to the device targeting the lanCfgSet function. It does not trigger from standard, legitimate network traffic or normal configuration updates. The flaw requires the device to process a malformed lanGw parameter value to cause the overflow.

Why should I care about this CVE if the device is internal?

Halo Surface Signal indicates this is unlikely to be internet-facing in standard deployments, as it relates to LAN configuration settings. However, you should still care if your device is accessible from any part of your network where an unauthorized user might send traffic, as it could lead to full device compromise.

Do I need to take action on my Tenda i29 devices?

Yes. First, identify all Tenda i29 units in your environment and determine if they are reachable over your network. Once you have an inventory, coordinate with your network security or infrastructure teams to assess the business risk and plan the necessary remediation steps to secure these appliances.

References

tenda.com/

Written by Nicholas Merritt

Nicholas Merritt is VP of Security Solutions at Halo Security. With more than 25 years across application security, vulnerability prioritization, and offensive security, he helps teams translate threat data into practical exposure validation and remediation focus. He authors Halo Threat Intelligence CVE advisories using Halo Surface Signal and H/A/L/O context to prioritize internet-facing risk.