CVE-2026-5706 in BT Mesh SDK
Summary
by MITRE • 08/28/2026
In Bluetooth Mesh SDK 6.1.4 and earlier, malformed extended advertisements can trigger out-of-bounds writes leading to stack corruption and remote code execution. These messages must come from a device that has already joined the network. Only provisioners supporting extended advertisements may be impacted.
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Analysis
by VulDB Data Team • 08/28/2026
The vulnerability identified in Bluetooth Mesh SDK versions 6.1.4 and earlier represents a critical security flaw within the protocol implementation, specifically affecting devices configured as provisioners that support extended advertisements. The core technical issue stems from an improper handling of malformed extended advertisement packets received during the network formation or maintenance phases. When such a device processes these specific data structures, it fails to adequately validate the length fields and bounds associated with incoming message payloads. This lack of rigorous input validation allows an attacker who has already gained entry into the Bluetooth Mesh network by successfully provisioning their device to craft specially crafted extended advertisement packets that exceed expected buffer boundaries.
Upon receiving this malformed data, the underlying C or C++ code responsible for parsing these advertisements performs a write operation beyond the allocated memory space on the stack. This out-of-bounds write corrupts adjacent memory locations, including critical control flow data such as return addresses and saved frame pointers. The immediate operational consequence of this memory corruption is unpredictable behavior ranging from application crashes to denial of service conditions where the affected node becomes unresponsive. However, given the nature of stack-based buffer overflows, a sophisticated attacker can leverage precise payload construction to overwrite specific memory locations with shellcode or ROP gadgets, thereby achieving remote code execution on the target device without further authentication or user interaction beyond initial network access.
From an industry standards perspective, this vulnerability aligns closely with CWE-120 Buffer Copy without Checking Size of Input and CWE-787 Out-of-bounds Write, which describe scenarios where input data is copied to a buffer without verifying that the size fits within the allocated space. In terms of attack vectors, this flaw facilitates actions consistent with MITRE ATT&CK technique T1546.002 Event Triggered Execution via Bluetooth protocols, as it allows an attacker to execute arbitrary code by triggering specific system behaviors through maliciously crafted wireless signals. The requirement for the attacker to be a provisioner who has already joined the network indicates that this is not a remote exploitation vector from outside the local mesh but rather an insider threat scenario or lateral movement technique within a compromised Bluetooth Mesh environment.
Mitigation strategies must prioritize immediate software updates, as vendors have released version 6.1.5 and later which address these boundary checks by implementing strict length validation before processing extended advertisement payloads. For environments where updating is not immediately feasible, network segmentation policies should be enforced to limit the scope of trusted provisioners, ensuring that only highly vetted devices are granted provisioning privileges. Additionally, deploying intrusion detection systems capable of analyzing Bluetooth Low Energy traffic for anomalous packet sizes and structures can provide an additional layer of defense against exploitation attempts targeting this specific flaw in legacy or unpatched nodes within critical infrastructure deployments.