Overview
The Common Vulnerabilities and Exposures (CVE) system has identified a significant vulnerability in the Bluetooth Low Energy (BLE) stack of Cypress PSoC4 v3.66, affecting a multitude of devices across various industries. Identified as CVE-2025-44557, this security flaw involves a state machine transition flaw that allows potential attackers to bypass pairing processes and authentication through a carefully crafted ‘pairing_failed’ packet. This vulnerability is particularly concerning due to the widespread use of BLE in devices such as smartphones, laptops, and IoT devices, making it a potentially vast attack surface.
Vulnerability Summary
CVE ID: CVE-2025-44557
Severity: Critical, CVSS score 8.1
Attack Vector: Network
Privileges Required: None
User Interaction: None
Impact: Potential system compromise and data leakage
Affected Products
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Product | Affected Versions
Cypress PSoC4 | v3.66
How the Exploit Works
The exploit takes advantage of a state machine transition flaw in the BLE stack. In essence, the state machine, which is responsible for managing the different stages of the BLE pairing process, can be manipulated by a malicious ‘pairing_failed’ packet. This packet causes the state machine to transition to a state where it believes the pairing process has failed and needs to restart. In this state, the authentication measures are temporarily disabled, allowing the attacker to bypass them entirely and gain unauthorized access to the system.
Conceptual Example Code
While the specific exploit code is beyond the scope of this blog post, the following pseudocode gives a rough idea of how an attacker might craft a malicious ‘pairing_failed’ packet:
def craft_malicious_packet():
packet = BLE_Packet()
packet.type = 'pairing_failed'
packet.payload = 'malicious_payload'
return packet
def send_packet(target, packet):
target_ble = connect_to_ble(target)
target_ble.send(packet)
target = 'target_device_address'
malicious_packet = craft_malicious_packet()
send_packet(target, malicious_packet)In this conceptual example, a malicious packet is crafted and sent to the target device. The packet type is set to ‘pairing_failed’, tricking the state machine into a state where authentication is bypassed, and the payload contains the malicious code that exploits this vulnerability. The resulting compromised system or data leakage could have severe consequences, particularly if the target device is a crucial component of a larger network.
For appropriate mitigation guidance, users are advised to apply the vendor patch as soon as possible. If immediate application of the patch is not possible, the use of a Web Application Firewall (WAF) or Intrusion Detection System (IDS) can serve as a temporary mitigation measure.