Z-Wave devices based on Silicon Labs 100, 200, and 300 series chipsets do not support encryption, allowing an attacker within radio range to take control of or cause a denial of service to a vulnerable device. An attacker can also capture and replay Z-Wave traffic. Firmware upgrades cannot directly address this vulnerability as it is an issue with the Z-Wave specification for these legacy chipsets. One way to protect against this vulnerability is to use 500 or 700 series chipsets that support Security 2 (S2) encryption. As examples, the Linear WADWAZ-1 version 3.43 and WAPIRZ-1 version 3.43 (with 300 series chipsets) are vulnerable.

Z-Wave devices based on Silicon Labs 700 series chipsets using S2 do not adequately authenticate or encrypt FIND_NODE_IN_RANGE frames, allowing a remote, unauthenticated attacker to inject a FIND_NODE_IN_RANGE frame with an invalid random payload, denying service by blocking the processing of upcoming events.

The Bluetooth Classic implementation in Silicon Labs iWRAP 6.3.0 and earlier does not properly handle the reception of an oversized LMP packet greater than 17 bytes, allowing attackers in radio range to trigger a crash in WT32i via a crafted LMP packet.

A denial-of-service vulnerability exists in the HTTP Server functionality of Micrium uC-HTTP 3.01.00. A specially crafted HTTP request can lead to denial of service. An attacker can send an HTTP request to trigger this vulnerability.

Silicon Labs Bluetooth Low Energy SDK before 2.13.3 has a buffer overflow via packet data. This is an over-the-air denial of service vulnerability in Bluetooth LE in EFR32 SoCs and associated modules running Bluetooth SDK, supporting Central or Observer roles.

An issue was discovered on Sigma Design Z-Wave S0 through S2 devices. An attacker first prepares a Z-Wave frame-transmission program (e.g., Z-Wave PC Controller, OpenZWave, CC1110, etc.). Next, the attacker conducts a DoS attack against the Z-Wave S0 Security version product by continuously sending divided "Nonce Get (0x98 0x81)" frames. The reason for dividing the "Nonce Get" frame is that, in security version S0, when a node receives a "Nonce Get" frame, the node produces a random new nonce and sends it to the Src node of the received "Nonce Get" frame. After the nonce value is generated and transmitted, the node transitions to wait mode. At this time, when "Nonce Get" is received again, the node discards the previous nonce value and generates a random nonce again. Therefore, because the frame is encrypted with previous nonce value, the received normal frame cannot be decrypted.

The Z-Wave specification requires that S2 security can be downgraded to S0 or other less secure protocols, allowing an attacker within radio range during pairing to downgrade and then exploit a different vulnerability (CVE-2013-20003) to intercept and spoof traffic.

Z-Wave devices from Sierra Designs (circa 2013) and Silicon Labs (using S0 security) may use a known, shared network key of all zeros, allowing an attacker within radio range to spoof Z-Wave traffic.