External risk intelligence

NullHub Missing Authentication Allows API Control.

CVE advisorySeverity: CRITICAL (CVSS 9.2)

CVE-2026-110616

The vulnerability affects a management API that listens on non-loopback network interfaces by default. Because the API provides control over agent instances, configuration, and credentials, it is frequently deployed in roles similar to an API gateway or management service. Its design as a networked management interface makes it commonly reachable in deployments where such API services are exposed.

Missing Authentication

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 vulnerability has been identified in NullHub software that could allow unauthorized access to its management API. This could enable attackers to control agent instances, alter configurations including sensitive credentials, and manage critical system functions. The main concern is confirming if our environment is running this software and if it is exposed.

Unauthenticated access to management controls.
Confirms potential unauthorized system compromise.
Verify usage and exposure of NullHub software.

Attack Path

How an attacker could exploit the issue

An unauthenticated attacker can reach the NullHub management API over the network and bypass authentication checks. This is possible because the `auth_token` field, which is used for authentication, defaults to null and is not properly assigned. By sending requests without the necessary authorization or origin headers, attackers can gain control over agent instances, modify configurations including sensitive provider credentials, and manage critical system components like cron jobs and MCP servers.

Attackers can reach the API externally.
Exploiting the null `auth_token` bypasses authentication.
Full control over agents and configurations.

Live Threat

Current exploitation, exposure, and threat context

NullHub's management API could be exposed, allowing unauthenticated attackers to control agent instances, alter configurations including provider credentials, and manage server tasks when the service is not restricted to loopback listeners.

Agent instances and configurations.
Network requests to non-loopback listeners.
Unauthorized control of system resources.

Operational Fix

Recommended remediation, mitigation, and detection steps

Security and infrastructure teams are likely responsible for NullHub, particularly those managing development platforms or agent-based systems. The first practical step is to identify all instances of NullHub, determine their reachability and criticality, and then assign ownership for remediation planning based on risk assessment.

Identify NullHub instances and assess exposure.
Confirm accountable application or platform owners.
Plan risk-based remediation and vendor coordination.

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.

Free EASM Trial See How Signal Works

Frequently asked questions

What is NullHub?

NullHub is an agent-based software platform used to manage distributed tasks, configurations, and system operations. It serves as a central controller for coordinating agent instances, managing cron-like background jobs, and handling Model Context Protocol (MCP) servers, often functioning similarly to an API gateway or administrative service.

What does CVE-2026-110616 mean for security?

This CVE describes a missing authentication weakness (CWE-306). Essentially, the software fails to verify the identity of anyone connecting to its management API. Because the security token defaults to an empty value and is never properly set, the system treats unauthorized requests as legitimate, allowing full access to administrative functions.

How do attackers trigger this vulnerability?

An attacker triggers this by sending network requests to the NullHub API without including specific authorization or origin headers. The issue occurs on non-loopback interfaces, meaning the service listens for connections from other machines. Requests restricted strictly to local-only or loopback interfaces do not trigger this specific authentication bypass.

Is my network environment at risk?

According to Halo Surface Signal, this vulnerability is highly relevant because the management API listens on non-loopback network interfaces by default. If your deployment makes this service reachable over the network rather than limiting it to local system processes, the interface is exposed to unauthorized manipulation of your credentials and agents.

What are the first steps to address this?

Start by conducting an inventory to locate all NullHub instances running in your environment. Once identified, evaluate their network reachability to determine which are exposed to untrusted traffic. Use this information to assign ownership to the appropriate teams and coordinate a risk-based plan to secure or update the affected systems.

References

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.