The vulnerability identified as CVE-2025-64342 resides in the Espressif Internet of Things Development Framework (esp-idf), specifically impacting the Bluetooth Low Energy (BLE) advertising mode of ESP32 devices. When the device is advertising, it listens for connection requests. If an attacker sends a connection request containing an invalid Access Address (AA) value of either 0x00000000 or 0xFFFFFFFF, the esp-idf fails to properly validate this exceptional condition. As a result, the advertising process may halt unexpectedly, and the Bluetooth controller erroneously signals a connection event to the host system. This misreporting causes the application layer to believe a connection has been successfully established, although no legitimate connection exists. This improper check for unusual conditions corresponds to CWE-754. The vulnerability affects esp-idf versions from 5.1 up to but not including the patched versions 5.1.7, 5.2.6, 5.3.5, 5.4.3, and 5.5.2. The issue can be exploited remotely over the network without authentication or user interaction, as the attacker only needs to send crafted BLE connection requests. While no exploits have been observed in the wild, the flaw could be leveraged to disrupt device advertising, potentially causing denial of service or misleading application logic dependent on connection state. The CVSS 4.0 vector (AV:N/AC:L/PR:N/UI:N/VC:N/VI:N/VA:L/SC:N/SI:N/SA:N) reflects a network attack vector with low complexity and no required privileges or user interaction, impacting availability and integrity at the application layer.

For European organizations deploying ESP32-based IoT devices using esp-idf, this vulnerability could lead to unexpected device behavior, including denial of service through halted advertising and incorrect connection state reporting. This may disrupt IoT operations, device management, and data collection processes, particularly in industrial, smart city, healthcare, and logistics applications where ESP32 devices are prevalent. Misleading connection status could cause application logic errors, potentially affecting system reliability and security monitoring. Although no known exploits exist, attackers within wireless range could exploit this flaw to degrade service or confuse device state, impacting operational continuity. The impact is more pronounced in environments with dense IoT deployments relying on BLE connectivity for critical functions. Additionally, the flaw could be leveraged as part of a broader attack chain targeting IoT infrastructure, increasing risk exposure for European enterprises and public sector entities using Espressif hardware.

European organizations should prioritize updating esp-idf to the fixed versions 5.5.2, 5.4.3, 5.3.5, 5.2.6, or 5.1.7 as soon as they become available. Until patches are applied, network-level controls should be implemented to monitor and filter anomalous BLE traffic, specifically connection requests with invalid Access Addresses (0x00000000 or 0xFFFFFFFF). Deploy BLE intrusion detection systems capable of identifying malformed connection attempts. Device firmware should be audited to ensure robust error handling for exceptional BLE conditions. Organizations should also review application logic that relies on connection events to validate connection state independently, preventing false assumptions. For critical deployments, consider segmenting BLE networks and limiting physical access to reduce attack surface. Maintain up-to-date asset inventories of ESP32 devices and monitor vendor advisories for further updates. Finally, incorporate this vulnerability into incident response plans to quickly detect and respond to potential exploitation attempts.