CVE-2021-34147

low-risk
Published 2021-09-07

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.

Do I need to act?

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0.10% chance of exploitation
EPSS score — low exploit probability
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Not on CISA KEV list
No confirmed active exploitation reported to CISA
?
Patch status unknown
Check vendor advisories for fix availability and mitigation guidance
6
CVSS 6.5/10 Medium
ADJACENT_NETWORK / LOW complexity

Affected Products (1)

Wireless Internet Connectivity For Embedded Devices

Affected Vendors

Cypress

References (4)

Technical Description https://dl.packetstormsecurity.net/papers/general/braktooth.pdf
Vendor Advisory https://www.cypress.com/documentation/datasheets/cyw20735b1-single-chip-bluetoot...
Technical Description https://dl.packetstormsecurity.net/papers/general/braktooth.pdf
Vendor Advisory https://www.cypress.com/documentation/datasheets/cyw20735b1-single-chip-bluetoot...
26
/ 100
low-risk
Severity 21/34 · High
Exploitability 0/34 · Minimal
Exposure 5/34 · Minimal