CVE-2026-79378 Overview
CVE-2026-79378 is a denial-of-service vulnerability in the btm_acl_handle() function of the Bestechnic Co., Ltd BES2300 Bluetooth Audio System-on-Chip (SoC) firmware. Attackers within Bluetooth range can send a crafted Logical Link Control and Adaptation Protocol (L2CAP) packet to trigger the flaw. Successful exploitation halts Bluetooth communication on the affected device. The issue is categorized under [CWE-400] Uncontrolled Resource Consumption. The vulnerability affects BES2300 firmware version 3.x and earlier releases.
Critical Impact
A single crafted L2CAP packet can disrupt Bluetooth audio services on affected BES2300-based devices without authentication or user interaction.
Affected Products
- Bestechnic BES2300 Bluetooth Audio SoC firmware v3.x
- Bestechnic BES2300 Bluetooth Audio SoC firmware earlier than v3.x
- Consumer audio products (earbuds, headphones, speakers) built on the BES2300 platform
Discovery Timeline
- 2026-09-08 - CVE-2026-79378 published to the National Vulnerability Database (NVD)
- 2026-09-09 - Last updated in NVD database
Technical Details for CVE-2026-79378
Vulnerability Analysis
The flaw resides in btm_acl_handle(), a function responsible for processing Asynchronous Connection-Less (ACL) traffic within the BES2300 Bluetooth stack. When the function receives a specifically malformed L2CAP packet, it fails to properly bound or validate the packet before consuming resources, leading to a denial-of-service state.
Because the BES2300 targets battery-powered audio peripherals, a Bluetooth disruption typically forces the user to power-cycle the device to restore service. The vulnerability requires no authentication, no pairing, and no user interaction beyond having the device in a discoverable or connectable state within radio range.
Root Cause
The root cause maps to [CWE-400] Uncontrolled Resource Consumption inside the ACL handling path. The btm_acl_handle() routine does not adequately constrain the resources consumed when processing anomalous L2CAP frames. The firmware processes attacker-controlled packet fields without enforcing safe bounds, resulting in an unrecoverable service state.
Attack Vector
Exploitation requires wireless Bluetooth proximity to a vulnerable BES2300 device. An attacker crafts an L2CAP packet with malformed length or field values and transmits it over the air. On receipt, the BES2300 firmware invokes btm_acl_handle(), which fails to sanitize the packet and enters a denial-of-service condition. No verified exploit code or public proof-of-concept is available at the time of publication. See the vendor's BestTechnic advisory for related technical details.
Detection Methods for CVE-2026-79378
Indicators of Compromise
- Bluetooth audio devices repeatedly disconnecting or requiring power-cycle to restore functionality
- Nearby unknown Bluetooth transmitters generating abnormal L2CAP traffic patterns
- Firmware crash or watchdog reset logs on managed BES2300-based devices, where telemetry is exposed
Detection Strategies
- Monitor Bluetooth Host Controller Interface (HCI) logs on paired hosts for repeated ACL disconnects tied to specific peer addresses
- Deploy over-the-air Bluetooth Low Energy (BLE) sniffers in sensitive environments to identify malformed L2CAP frames
- Correlate user-reported device outages against timestamps of nearby unauthorized Bluetooth activity
Monitoring Recommendations
- Track firmware versions of BES2300-based audio devices across the fleet using mobile device management (MDM) inventory
- Alert on repeated Bluetooth reconnection storms from managed endpoints, which may indicate proximity attacks
- Ingest wireless intrusion detection telemetry into a centralized SIEM for correlation with physical location data
How to Mitigate CVE-2026-79378
Immediate Actions Required
- Inventory all devices built on the Bestechnic BES2300 SoC and identify those running firmware v3.x or earlier
- Disable Bluetooth on affected devices when not in active use, particularly in public or high-risk locations
- Contact device manufacturers to obtain firmware updates that address the btm_acl_handle() flaw
Patch Information
Bestechnic has published a related advisory at the BestTechnic CVE-2026-79376 Report. Downstream device vendors that integrate the BES2300 SoC must repackage and distribute the corrected firmware to end users. Consult the Bestechnic homepage and individual device manufacturers for release timelines and update procedures.
Workarounds
- Keep affected audio devices in non-discoverable mode when paired and disable pairing when unused
- Operate BES2300-based devices only in trusted physical environments until firmware updates are available
- Restrict use of vulnerable devices in executive, government, or high-value settings where targeted DoS attacks are plausible
Disclaimer: This content was generated using AI. While we strive for accuracy, please verify critical information with official sources.