CVE-2026-110616 in NullHub
Summary
by MITRE • 10/14/2026
NullHub through 2026.5.29 contains a missing authentication vulnerability that allows unauthenticated attackers to access the /api/* management API because the auth_token field defaults to null and is never assigned. Attackers sending requests without Authorization or Origin headers to non-loopback listeners can control agent instances, rewrite configurations including provider credentials, and manage cron jobs and MCP servers.
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Analysis
by VulDB Data Team • 10/14/2026
The vulnerability identified in NullHub versions up through 2026.5.29 represents a critical failure in access control mechanisms within the application's management API interface. This flaw is categorized as CWE-306: Missing Authentication for Critical Function, where the system fails to require authentication credentials before allowing actions that impact security posture or data integrity. The root cause lies in the implementation of the auth_token field, which defaults to a null value and is never properly assigned during the initialization process for non-loopback listeners. Consequently, any request directed at the /api/* endpoints without explicit Authorization or Origin headers bypasses authentication checks entirely. This design oversight effectively renders the management interface publicly accessible if the service is bound to an external network interface rather than strictly localhost, exposing sensitive administrative capabilities to unauthenticated actors on the same network segment or potentially over the internet depending on firewall rules and deployment configuration.
From a technical perspective, the absence of token validation allows attackers to interact with critical system components without any form of identity verification. The management API provides high-privilege operations including agent instance control, configuration rewriting, cron job management, and MCP server administration. By exploiting this missing authentication check, an attacker can send crafted HTTP requests that are processed as valid administrative commands. This capability enables the modification of provider credentials stored within the application's configuration files, which may include API keys for cloud services or other third-party integrations. Such unauthorized access to credential stores poses a severe risk as it can lead to further compromise of downstream systems and data associated with those providers. Additionally, the ability to manage cron jobs allows attackers to schedule persistent malicious tasks that survive system reboots, facilitating long-term persistence within the environment.
The operational impact of this vulnerability is substantial due to the breadth of control granted over agent instances and MCP servers. An unauthenticated attacker can take full command of managed agents, potentially using them as pivoting points for lateral movement within a network or launching attacks against other targets from trusted internal IP addresses. The manipulation of cron jobs introduces risks related to resource exhaustion, data exfiltration schedules, or the execution of arbitrary code if the scheduled tasks are not sufficiently sandboxed. Furthermore, rewriting provider credentials can disrupt service availability by invalidating legitimate access tokens or redirecting sensitive operations to attacker-controlled endpoints for interception and abuse. This scenario aligns with ATT&CK technique T1078: Valid Accounts, as the attacker leverages a functional but unauthenticated pathway that mimics valid administrative sessions, and potentially T1496: Remote Service Vulnerability if exploited in conjunction with other network-level flaws to expand access beyond the immediate application boundary.
Mitigation strategies must prioritize immediate remediation of the authentication logic within the NullHub codebase. The primary fix involves ensuring that all endpoints under /api/* enforce strict authentication checks, validating the presence and integrity of auth_token or equivalent credentials before processing any request. Developers should implement a default-deny approach where access is explicitly granted only to authenticated users with appropriate roles. For organizations unable to immediately patch the software, network-level controls are essential. Administrators must ensure that management APIs are bound exclusively to loopback interfaces (127.0.0.1 or ::1) and not exposed to external networks until a fix is deployed. If remote access is required for administrative purposes, it should be secured through additional layers such as VPNs with strong mutual authentication, reverse proxies enforcing OAuth2 or JWT validation, or IP whitelisting restricted to known trusted management stations. Regular security audits of API endpoints are recommended to detect similar misconfigurations in other services within the ecosystem.