CVE-2021-34146

Name: CVE-2021-34146
Creator: NVD / NIST
Published: 2021-09-07T07:15:07.327+00:00
License: https://creativecommons.org/publicdomain/zero/1.0/

MEDIUMCVSS 6.5/10EPSS 0.56%

Last modified Jun 17, 2026

CVE-2021-34146 is a medium-severity vulnerability rated 6.5/10 on the CVSS scale. The Bluetooth Classic implementation in the Cypress CYW920735Q60EVB does not properly handle the reception of continuous unsolicited LMP responses, allowing attackers in radio range to trigger a denial of service and restart (crash) of the device by flooding it with LMP_AU_Rand packets after the paging procedure.. EPSS estimates a 0.56% chance of exploitation in the next 30 days.

Description

The Bluetooth Classic implementation in the Cypress CYW920735Q60EVB does not properly handle the reception of continuous unsolicited LMP responses, allowing attackers in radio range to trigger a denial of service and restart (crash) of the device by flooding it with LMP_AU_Rand packets after the paging procedure.

Metrics

CVSS 3.1

6.5/10

CVSS:3.1/AV:A/AC:L/PR:N/UI:N/S:U/C:N/I:N/A:H

EPSS Probability

0.56%

42.5th percentile

Probability of exploitation in the next 30 days. Learn more

Affected Software

Vendor	Product	Versions
Cypress	Cyw920735q60evb-01 Firmware	All versions
Cypress	Cyw20735b1 Firmware	All versions

References

https://dl.packetstormsecurity.net/papers/general/braktooth.pdfTechnical Description, Third Party Advisory
https://www.cypress.com/documentation/datasheets/cyw20735b1-single-chip-bluetooth-transceiver-wireless-input-devicesVendor Advisory
https://dl.packetstormsecurity.net/papers/general/braktooth.pdfTechnical Description, Third Party Advisory
https://www.cypress.com/documentation/datasheets/cyw20735b1-single-chip-bluetooth-transceiver-wireless-input-devicesVendor Advisory

Timeline

Published: Sep 7, 2021
Last Modified: Jun 17, 2026
Status: Modified

Frequently Asked Questions

What is CVE-2021-34146?

How severe is CVE-2021-34146?

CVE-2021-34146 has a CVSS score of 6.5/10 (MEDIUM severity). The EPSS model estimates a 0.56% probability of exploitation in the next 30 days.

How do I fix CVE-2021-34146?

Check the vendor references and advisories linked above for patched versions and mitigation guidance. You can also run a Strix scan to test if your systems are affected.

Are you affected by CVE-2021-34146?

Run a free Strix scan to check your systems for this vulnerability.

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Source: NVD / NIST