External risk intelligence

Tenda i29 Buffer Overflow Vulnerability in Login Function

CVE advisorySeverity: CRITICAL (CVSS 9.8)

CVE-2023-50986

The vulnerability exists in the login function of a Tenda wireless access point. Such networking devices are frequently deployed as edge gateways or management interfaces accessible over a network, and login portals for these devices are commonly exposed or reachable in environments where they provide network access.

Out-of-bounds Write

Tenda I29 Firmware

1.0.0.21.0.0.5

Halo Surface Signal: 4 out of 5 — likely to be public-facing.

External exposure likelihood

Horizon Alert

Summary of the vulnerability and why it matters

This advisory details a critical vulnerability in Tenda i29 devices that could allow unauthorized access and control. The issue involves a buffer overflow in the device's login function, which, if exploited, could lead to significant compromise of the affected network infrastructure. While specific business impact is not detailed, the nature of the vulnerability underscores the importance of ensuring the security of network edge devices.

Vulnerability allows unauthorized system access.
This concerns network devices managing access.
Confirm relevance and exposure of Tenda devices.

Attack Path

How an attacker could exploit the issue

An attacker could target the login functionality of a Tenda i29 device accessible over the network. By sending specially crafted input to the `sysLogin` function, an attacker could trigger a buffer overflow, potentially leading to the execution of arbitrary code and full control over the device.

Requires network access to the device.
Triggered by sending malformed input to login.
Allows full device compromise.

Live Threat

Current exploitation, exposure, and threat context

A buffer overflow vulnerability in the login function of Tenda i29 devices could allow an unauthenticated attacker to crash the device or potentially execute arbitrary code. This could occur when a specially crafted 'time' parameter is sent to the device's login endpoint. The impact depends on whether the device is configured in a way that exposes its login interface to an attacker-controlled network.

Device availability could be impacted.
Unauthenticated network access could trigger.
Denial of service is a realistic consequence.

Operational Fix

Recommended remediation, mitigation, and detection steps

This vulnerability in Tenda i29 firmware requires a coordinated response. Infrastructure or network teams are likely responsible for managing these devices, but identifying the specific business owner and confirming the exposure of affected devices are the critical first steps. Once prioritized, a remediation plan involving vendor coordination and potential maintenance window scheduling should be executed.

Identify accountable infrastructure/network teams.
Verify device reachability and business criticality.
Coordinate with Tenda for firmware updates.

Supplementary metadata

CVSS vector

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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 serves as infrastructure hardware that manages traffic for connected users. The affected firmware versions, specifically 1.0.0.2 and 1.0.0.5, include the system software that handles core device operations and administrative functions, such as the login portal where this vulnerability resides.

What is a buffer overflow vulnerability?

A buffer overflow occurs when a program writes more data to a memory buffer than it can hold, causing it to overwrite adjacent memory. In CVE-2023-50986, this memory corruption happens within the sysLogin function. This is categorized under CWE-787 and CWE-120, meaning the device fails to properly restrict input size, potentially allowing an attacker to manipulate the device's execution flow.

How is this vulnerability triggered?

An attacker triggers this flaw by sending a specially crafted 'time' parameter to the device's sysLogin function over the network. It requires sending malformed input to the login endpoint. Normal, legitimate login attempts that do not include malicious, oversized data in this specific parameter do not trigger the overflow, as the vulnerability is dependent on the exploitation of the input handling logic.

Who should be concerned about CVE-2023-50986?

Anyone managing Tenda i29 access points should care. According to Halo Surface Signal, these devices are often used as edge gateways, making their management interfaces frequent targets. If the login portal is reachable over a network—especially one accessible by unauthorized parties—the risk is higher. You should prioritize assessment if your devices are not restricted to trusted, internal-only management subnets.

What is the first step to address this?

First, identify all Tenda i29 units in your infrastructure and confirm their current firmware version. Check if the login interface is accessible from untrusted networks and restrict that access immediately if possible. Contact Tenda to verify the availability of an update that addresses the sysLogin vulnerability, and plan to apply it during a scheduled maintenance window to ensure device stability.

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.