CVE-2026-79378 in Audio SoC firmware
Summary
by MITRE • 09/08/2026
An issue in the btm_acl_handle() function of Bestechnic Co., Ltd BES2300 Bluetooth Audio SoC firmware v3.x and earlier allows attackers to cause a Denial of Service (DoS) via sending a crafted L2CAP packet.
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Analysis
by VulDB Data Team • 09/08/2026
The vulnerability identified within the BEST2300 series Bluetooth Audio System on Chip, specifically affecting firmware versions 3.x and prior releases, centers on a critical flaw in the Link Layer Control Protocol handling logic implemented by the btm_acl_handle function. This component is responsible for managing Asynchronous Connectionless links, which are fundamental to Bluetooth communication for transmitting data that does not require strict timing or sequencing guarantees. The core technical deficiency lies in the insufficient validation of incoming L2CAP packets before they are processed further up the protocol stack. When an attacker sends a specially crafted L2CAP packet containing malformed headers, invalid payload lengths, or unexpected control codes, the function fails to perform adequate bounds checking and state verification. This lack of rigorous input sanitization allows malicious data structures to bypass standard error handling routines, leading directly to memory corruption or logic errors within the firmware execution environment.
From a technical perspective, this flaw represents a classic instance of improper input validation that can lead to denial of service conditions through resource exhaustion or system crash. The btm_acl_handle function likely attempts to parse fields from the crafted packet without verifying their integrity against expected protocol specifications defined by Bluetooth SIG standards. When these malformed packets are processed, they may trigger undefined behavior in the underlying C code, such as buffer overflows, null pointer dereferences, or infinite loops within the connection management state machine. Because this function operates at a low level of the Bluetooth stack, an exploit does not require authentication or prior pairing with the device. An attacker simply needs to be within radio range and capable of transmitting raw L2CAP packets via standard Bluetooth interfaces, making this a remote attack vector that is relatively easy to execute against vulnerable devices in public spaces or targeted environments.
The operational impact of this vulnerability is primarily focused on service availability rather than data confidentiality or integrity. Successful exploitation results in the denial of service for the affected BEST2300 device, manifesting as a complete freeze of the Bluetooth subsystem or a hard reboot of the SoC. For audio-centric devices such as wireless headphones, speakers, or hearing aids that rely on this chipset, this disruption means an immediate loss of connectivity and functionality. Users may experience sudden disconnections during playback, inability to pair with new devices, or total unresponsiveness until power is cycled. In enterprise or IoT deployments where these chips might be integrated into larger systems, the instability could propagate errors to host processors if error handling mechanisms are not robustly implemented at higher layers, potentially causing broader system degradation beyond just the Bluetooth radio interface.
This vulnerability aligns with CWE-20 Improper Input Validation and is often associated with CWE-400 Uncontrolled Resource Consumption when the malformed packets cause excessive CPU usage or memory leaks leading to a crash. In terms of offensive security frameworks, this attack vector maps closely to MITRE ATT&CK technique T1595 Active Scanning, specifically within the context of Bluetooth enumeration and exploitation phases where adversaries probe for weaknesses in wireless protocols. The ability to disrupt service via crafted packets is also consistent with patterns seen in other Bluetooth stack vulnerabilities such as BlueBorne or Bluedoor, highlighting a persistent challenge in embedded firmware development regarding secure protocol implementation.
Mitigation strategies must focus on both immediate patching and long-term architectural improvements. Manufacturers should urgently release updated firmware versions that include rigorous validation checks within the btm_acl_handle function to ensure all L2CAP packet fields conform strictly to Bluetooth Core Specification requirements before processing. This includes validating payload lengths, checking for valid connection handles, and ensuring control codes are recognized and handled safely. For organizations deploying these devices in critical infrastructure or sensitive environments, it is advisable to disable discoverable mode when not actively pairing new devices to reduce the attack surface exposed to remote attackers. Additionally, implementing network segmentation can limit the ability of potential adversaries to reach vulnerable endpoints via Bluetooth radio waves if physical proximity cannot be strictly controlled. Long-term remediation should involve adopting secure coding practices and formal verification methods for critical protocol handlers in embedded systems to prevent similar input validation flaws from recurring in future firmware iterations.