CVE-2020-26560 in Mesh
Summary
by MITRE • 05/25/2021
Bluetooth Mesh Provisioning in the Bluetooth Mesh profile 1.0 and 1.0.1 may permit a nearby device, reflecting the authentication evidence from a Provisioner, to complete authentication without possessing the AuthValue, and potentially acquire a NetKey and AppKey.
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Analysis
by VulDB Data Team • 11/04/2025
The vulnerability identified as CVE-2020-26560 resides within the Bluetooth Mesh provisioning process, specifically affecting versions 1.0 and 1.0.1 of the Bluetooth Mesh profile. This flaw represents a critical security weakness in the authentication mechanism that governs how devices establish trust and secure communication within Bluetooth Mesh networks. The Bluetooth Mesh specification defines a sophisticated architecture for connecting multiple Bluetooth devices into a unified network where devices can communicate through intermediate nodes, creating complex mesh topologies for applications ranging from smart lighting to industrial IoT systems. The provisioning phase is fundamental to this architecture as it establishes the cryptographic keys and network parameters that secure all subsequent communications between mesh nodes.
The technical flaw stems from an improper implementation of the authentication process during provisioning, where a malicious nearby device can exploit a reflection attack pattern. In normal operation, the provisioning protocol requires both the Provisioner and the Provisionee to demonstrate possession of the shared AuthValue through a challenge-response mechanism. However, this vulnerability allows an attacker to reflect authentication evidence back to the Provisioner, effectively bypassing the requirement for the attacker to actually possess the AuthValue. This occurs because the protocol does not adequately validate that the authentication response originates from the legitimate device that should possess the shared secret. The flaw operates at the protocol level and affects the cryptographic handshake that establishes the secure channel for key distribution, creating a scenario where an attacker can complete the provisioning process without meeting the necessary authentication requirements.
The operational impact of this vulnerability is significant and far-reaching within Bluetooth Mesh deployments. An attacker positioned within the transmission range of a mesh network can potentially gain unauthorized access to the network by completing the provisioning process without possessing the required cryptographic credentials. This enables the attacker to acquire critical network keys including the NetKey and AppKey, which provide access to all communications within the mesh network. Once these keys are obtained, the attacker can monitor, modify, or inject messages into the network, potentially leading to complete network compromise. The vulnerability is particularly concerning because it affects devices that may be deployed in sensitive environments such as industrial control systems, smart buildings, or healthcare facilities where network integrity and security are paramount. The attack requires only proximity to the network and does not necessitate sophisticated equipment or deep technical knowledge beyond understanding the Bluetooth Mesh protocol.
Mitigation strategies for this vulnerability must address both the immediate protocol-level issues and broader network security considerations. Organizations should prioritize upgrading to Bluetooth Mesh profile versions that have addressed this vulnerability, typically version 1.0.2 or later, where the authentication mechanism has been properly implemented to prevent reflection attacks. Network administrators should implement additional security controls such as physical security measures to prevent unauthorized access to provisioning phases, and consider deploying network monitoring solutions that can detect anomalous provisioning activities. The vulnerability aligns with CWE-310, which specifically addresses cryptographic weaknesses in authentication mechanisms, and relates to ATT&CK technique T1046 for network service scanning and T1566 for phishing attacks that could be leveraged to position attackers near target networks. Device manufacturers should ensure proper implementation of the Bluetooth Mesh specification's security requirements, including thorough testing of authentication flows and validation of the challenge-response mechanism. The security community should also consider implementing network segmentation and access controls that limit the potential impact of a compromised provisioning process, while maintaining the operational integrity of Bluetooth Mesh networks that provide essential connectivity for numerous IoT applications.