External risk intelligence

Comfast CF-N1-S Stack Buffer Overflow in Web Management Interface

CVE advisorySeverity: CRITICAL (CVSS 9.3)

CVE-2026-94003

The vulnerability resides in the web management interface of a network device, which is commonly deployed as an externally reachable gateway or management portal.

Memory Corruption

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

A remote vulnerability in a network device's web management interface could allow an attacker to gain control of the system. The issue is publicly disclosed, meaning it may be actively exploited.

  • A web interface flaw allows remote system takeover.
  • Public exploit increases risk to exposed systems.
  • Confirm relevance and exposure to affected devices.

Attack Path

How an attacker could exploit the issue

An attacker can remotely trigger this vulnerability by sending specially crafted input to the web management interface. This input targets the `get_css_path_from_uri` function within the `/cgi-bin/mbox-config` file. Successful manipulation can lead to a stack-based buffer overflow, potentially allowing an attacker to gain control over the device.

  • No authentication required for attack.
  • Triggered by malformed URI input.
  • Risk of remote code execution.

Live Threat

Current exploitation, exposure, and threat context

A remote attacker could remotely trigger a stack-based buffer overflow in the web management interface by manipulating the `get_css_path_from_uri` function. This may allow unauthorized access to system resources or disrupt normal service behavior.

  • System configuration and data.
  • Remote manipulation of a web interface function.
  • Potential disruption of service availability.

Operational Fix

Recommended remediation, mitigation, and detection steps

For this CVE, system owners and infrastructure teams are likely responsible for identifying and remediating the vulnerability. The first practical step is to locate all instances of the affected Comfast CF-N1-S, determine their network exposure and business criticality, and identify the accountable owner before planning remediation.

  • Identify affected Comfast devices.
  • Confirm network exposure and criticality.
  • Plan remediation based on risk.

Supplementary metadata

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.

Frequently asked questions

What is the Comfast CF-N1-S?

The Comfast CF-N1-S is a piece of network hardware, typically functioning as a gateway or routing device. It includes a Web Management Interface that allows administrators to configure system settings, manage network traffic, and maintain the device's operational state through a browser-based portal.

How does CVE-2026-94003 work?

This vulnerability is a stack-based buffer overflow, classified under CWE-121. It occurs when the device's software fails to properly manage the amount of data written to a memory buffer. In this specific case, sending malformed input to the get_css_path_from_uri function within the web interface allows an attacker to overwrite adjacent memory, which can lead to unauthorized control of the system.

Does any specific action trigger this bug?

Yes, the vulnerability is triggered by sending a specially crafted URI to the /cgi-bin/mbox-config component of the web interface. Because the flaw exists in how the interface processes inputs, it does not require an attacker to have a valid user account or password to initiate the attack; however, sending standard, non-malicious web requests to the interface will not trigger this overflow.

Is my device at risk if it is not on the internet?

Halo Surface Signal identifies this as an external risk, meaning the primary threat comes from devices directly reachable via the internet. If your Comfast CF-N1-S is strictly segmented within an internal, non-routable network, the likelihood of a remote attacker reaching the vulnerable interface is significantly reduced, though internal threats remain a consideration.

What should I do to address CVE-2026-94003?

Start by performing an inventory to locate all Comfast CF-N1-S units in your environment. Once identified, evaluate whether these devices are exposed to the public internet and assess their business criticality. Ensure you have identified the internal owner for these systems so you can coordinate the next steps for applying security updates or restricting access to the management interface.

References