What’s Vulnerable › Vulnerabilities

CVE-2021-34147

• Severity: medium (CVSS 6.5 v3.1)
• Exploited in the wild: not listed in CISA KEV
• EPSS: 0.6% probability of exploitation in the next 30 days
• Public exploit or detection template: none known
• Published: 2021-09-07 · updated 2026-06-17

Description

The Bluetooth Classic implementation in the Cypress WICED BT stack through 2.9.0 for CYW20735B1 does not properly handle the reception of a malformed LMP timing accuracy response followed by multiple reconnections to the link slave, allowing attackers to exhaust device BT resources and eventually trigger a crash via multiple attempts of sending a crafted LMP timing accuracy response followed by a sudden reconnection with a random BDAddress.

Affected products

• Cypress Wireless Internet Connectivity For Embedded Devices: through 2.9.0

References

• https://dl.packetstormsecurity.net/papers/general/braktooth.pdf
• https://www.cypress.com/documentation/datasheets/cyw20735b1-single-chip-bluetooth-transceiver-wireless-input-devices
• https://dl.packetstormsecurity.net/papers/general/braktooth.pdf
• https://www.cypress.com/documentation/datasheets/cyw20735b1-single-chip-bluetooth-transceiver-wireless-input-devices

Get alerted when CVE-2021-34147 or the next vulnerability affects your stack