CVE-2026-19244 in nanobot
Summary
by MITRE • 08/07/2026
A vulnerability was detected in HKUDS nanobot up to 0.2.1. The affected element is the function connect_mcp_servers of the file nanobot/agent/tools/mcp.py of the component MCP enabledTools Scope Handler. Performing a manipulation results in improper access controls. The attack is possible to be carried out remotely. The exploit is now public and may be used. Upgrading to version 0.3.0 is sufficient to fix this issue. The patch is named 4436. You should upgrade the affected component. Multiple issues were reported to the project. They reacted with a high level of professionalism and kindness: "Both reports describe the same root cause: MCP resource and prompt wrappers could be registered outside the intended enabledTools scope. The registration boundary was corrected".
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Analysis
by VulDB Data Team • 08/07/2026
The vulnerability identified in HKUDS nanobot version 0.2.1 and earlier represents a critical access control flaw within the MCP enabledTools Scope Handler component. This issue specifically affects the connect_mcp_servers function located in nanobot/agent/tools/mcp.py, where improper access controls allow unauthorized manipulation of system resources. The vulnerability stems from a boundary violation in how MCP resource and prompt wrappers are registered, creating a scenario where components can be registered outside their intended scope. This flaw constitutes a direct violation of the principle of least privilege and represents a classic case of inadequate access control implementation that falls under CWE-284 Access Control.
The remote exploitability of this vulnerability presents significant operational risks to organizations utilizing the affected nanobot component. Attackers can leverage this weakness to manipulate the MCP enabledTools scope handler from external positions, potentially gaining unauthorized access to system resources and capabilities beyond what was originally intended. The public availability of exploits for this vulnerability means that threat actors can immediately capitalize on this weakness without requiring specialized knowledge or tools. This situation aligns with ATT&CK technique T1068 Remote Services and demonstrates how improper access control mechanisms can create persistent attack vectors within networked systems.
The technical root cause of this vulnerability lies in the improper enforcement of scope boundaries for MCP resource registration. When components are registered outside their intended enabledTools scope, they can potentially access or manipulate resources that should remain restricted to authorized contexts. This boundary violation creates a pathway for privilege escalation and unauthorized system manipulation. The fix implemented in version 0.3.0 addresses this by correcting the registration boundary, ensuring that MCP resource and prompt wrappers can only be registered within their designated scope as originally intended.
Organizations deploying HKUDS nanobot components must prioritize immediate remediation through upgrading to version 0.3.0 or later, which incorporates the patch 4436 addressing this specific access control weakness. The professional response from the project maintainers demonstrates effective vulnerability management practices, acknowledging that both reported issues stemmed from the same fundamental problem and implementing a comprehensive solution. This remediation addresses the core architectural flaw in scope enforcement rather than merely patching symptoms, providing a more robust long-term solution against similar vulnerabilities.
The broader implications of this vulnerability extend beyond immediate exploitation risks to highlight the importance of proper scope management in distributed system components. System administrators should conduct thorough security assessments of all MCP-enabled tools and verify that registration boundaries are properly enforced across all components. This vulnerability serves as a reminder of how seemingly isolated access control issues can create significant security risks in interconnected systems, emphasizing the need for comprehensive security testing and validation of scope mechanisms within software components that handle sensitive resource management operations.