CVE-2026-47722 in nebula-mesh
Summary
by MITRE • 07/23/2026
nebula-mesh is a self-hosted control plane for Slack Nebula mesh virtual private network. Prior to version 0.3.2, `internal/configgen/generator.go:86,108,119` interpolates the operator-supplied `ListenHost` and `TunDevice` fields raw into a `text/template` that produces the agent's `config.yml`. `internal/web/advanced.go:20-35` accepts both with only `strings.TrimSpace` — no character or shape validation. Version 0.3.2 fixes the issue.
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Analysis
by VulDB Data Team • 07/23/2026
The nebula-mesh vulnerability represents a critical command injection flaw in the control plane's configuration generation process. This vulnerability exists in versions prior to 0.3.2 where the system fails to properly sanitize user-supplied input before incorporating it into template-based configuration files. The specific code paths affected are located in internal/configgen/generator.go at lines 86, 108, and 119 where the ListenHost and TunDevice fields are directly interpolated into text/template structures without adequate validation or sanitization measures.
The technical implementation of this vulnerability stems from insufficient input validation within the web interface handling component. The internal/web/advanced.go file at lines 20-35 processes both ListenHost and TunDevice parameters through a minimal strings.TrimSpace operation that removes only leading and trailing whitespace characters. This basic sanitization approach fails to address more sophisticated injection vectors including special characters, escape sequences, or template syntax that could be exploited by malicious operators. The lack of comprehensive validation creates a path for attackers to inject arbitrary commands or manipulate the generated configuration files through carefully crafted input values.
The operational impact of this vulnerability is severe as it allows an authenticated attacker with control plane access to execute arbitrary commands on the system hosting the nebula-mesh control plane. When the configuration generator processes malicious input, the interpolated template content can contain shell command execution directives that get executed during agent configuration generation or subsequent processing steps. This creates a privilege escalation scenario where attackers can potentially gain unauthorized access to underlying system resources, modify network configurations, or establish persistent backdoors within the mesh network infrastructure.
This vulnerability aligns with CWE-74 and CWE-94 categories from the Common Weakness Enumeration database, specifically addressing weaknesses in external control of system or configuration settings and improper neutralization of special elements used in code. From the MITRE ATT&CK framework perspective, this represents a technique for privilege escalation through command injection and configuration manipulation. The attack vector leverages legitimate administrative functions to execute malicious payloads within the control plane environment.
The remediation implemented in version 0.3.2 addresses this vulnerability by introducing proper input validation and sanitization mechanisms that prevent dangerous characters and sequences from being processed within the template interpolation context. This fix ensures that user-supplied values for ListenHost and TunDevice fields undergo comprehensive validation before being incorporated into configuration templates, eliminating the risk of command injection attacks while maintaining functional integrity of the mesh network control plane operations.
The vulnerability demonstrates a classic example of insufficient input sanitization in web applications and highlights the importance of validating all user-provided data within template processing contexts. Organizations using nebula-mesh should immediately update to version 0.3.2 or later and conduct thorough security reviews of their control plane configurations to ensure no malicious input has been processed through the vulnerable code paths.