CVE-2021-34147 json
The Bluetooth Classic implementation in the Cypress WICED BT stack through 2.9.0 for CYW20735B1 does not properly handle the reception of a…
published 2021-09-07 5 y ago modified 2026-06-17 4 mo ago also EUVD-2021-20809
- cvss
- 6.5
- version 3.1, NVD
- cisa kev
- Not listed
- not in CISA's catalog
- epss
- 0.6%
- EPSS 0.6% chance of exploitation in 30 days, percentile 48%
- public exploits
- 0
- none known
Summary
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.
Patch / fix
- bluez-firmware Debian 14, Debian 13, Debian 12 1.2-8
debian advisories DEBIAN-CVE-2021-34147
Exploit prediction
0.59% chance of exploitation in the next 30 days, higher than 48% of all scored CVEs (FIRST EPSS, 2026-11-08).
CVSS scores
| assigned by | version | score | vector |
|---|---|---|---|
| NVD | 3.1 | 6.5 | CVSS:3.1/AV:A/AC:L/PR:N/UI:N/S:U/C:N/I:N/A:H |
| NVD | 2.0 | 6.1 | AV:A/AC:L/Au:N/C:N/I:N/A:C |
References
-
cypress.com
/documentation/datasheets/cyw20735b1-single-chip-bluetooth-transceiver-wireless-input-devices
vendor-advisory
-
dl.packetstormsecurity.net
/papers/general/braktooth.pdf
technical-description, third-party-advisory
Sources
- CVE List CVE-2021-34147
- NVD CVE-2021-34147
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