CVE-2026-47722

Deferred Deferred - Pending Action

Command Injection in Nebula-Mesh VPN Control Plane

Publication date: 2026-07-23

Last updated on: 2026-07-30

Assigner: GitHub, Inc.

Description

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.

CVSS Scores

EPSS Scores

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Meta Information

Published

2026-07-23

Last Modified

2026-07-30

Generated

2026-08-13

AI Q&A

2026-07-23

EPSS Evaluated

2026-08-11

NVD

CVE-2026-47722

Affected Vendors & Products

Vendor	Product	Version / Range
forgekeep	nebula-mesh	to 0.3.2 (exc)
forgekeep	nebula-mesh	From 0.3.2 (inc)
nebula-mesh	nebula_mesh	to 0.3.2 (exc)

Helpful Resources

Exploitability

CWE

KEV

CWE ID	Description
CWE-94	The product constructs all or part of a code segment using externally-influenced input from an upstream component, but it does not neutralize or incorrectly neutralizes special elements that could modify the syntax or behavior of the intended code segment.

Attack-Flow Graph

Executive Summary

CVE-2026-47722 is a YAML injection vulnerability in nebula-mesh versions before 0.3.2. It occurs because user-supplied fields like ListenHost and TunDevice are directly interpolated into a text template without proper validation or escaping. This allows attackers with operator privileges to inject malicious YAML payloads into the agent's config.yml file.

Detection Guidance

To detect this vulnerability, check if your nebula-mesh version is below 0.3.2. Run: nebula-mesh version. Inspect configuration files for unexpected YAML structures or special characters in ListenHost or TunDevice fields.

Impact Analysis

An attacker could exploit this to escalate privileges, such as promoting a host to a lighthouse or relay, or altering hidden configuration flags. Even with authorization fixes, the agent blindly trusts server-provided configs, making exploitation still possible.

Compliance Impact

This vulnerability could impact compliance with GDPR and HIPAA by enabling unauthorized configuration changes through YAML injection. Attackers with operator privileges could alter sensitive settings, potentially violating data protection requirements for confidentiality and integrity.

Mitigation Strategies

Upgrade to nebula-mesh version 0.3.2 or later. If upgrading is not possible, restrict ListenHost and TunDevice to safe character sets in parseAdvancedFromForm or disable advanced overrides until patched.

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