HOMEVULNERABILITIESCVE-2021-34148
MEDIUM

CVE-2021-34148

NVD-CWE-noinfoPublished: September 7, 2021· Updated: Jun 17, 2026

6.5
CVSS v3.1

Official Description

The Bluetooth Classic implementation in the Cypress WICED BT stack through 2.9.0 for CYW20735B1 devices does not properly handle the reception of LMP_max_slot with a greater ACL Length after completion of the LMP setup procedure, allowing attackers in radio range to trigger a denial of service (firmware crash) via a crafted LMP packet.

NVD Source

Technical Analysis

CVE-2021-34148 requires adjacent network access, limiting remote exploitation but still posing risk in shared or local network environments.

The vulnerability requires no privileges and no user interaction, making it a prime target for automated exploitation campaigns and worm-like propagation.

A successful exploit results in availability disruption (denial of service), with a CVSS base score of 6.5.

CVSS v3.1 Vector Breakdown

Exploitability
Attack VectorAdjacent
Attack ComplexityLow
Privileges Req.None
User InteractionNone
ScopeUnchanged
Impact
ConfidentialityNone
IntegrityNone
AvailabilityHigh
CVSS:3.1/AV:A/AC:L/PR:N/UI:N/S:U/C:N/I:N/A:H

Affected Vendors & Products

cypress2 product(s)
wireless internet connectivity for embedded devicescyw20735b1
Source: NVD CPE · 2 total CPE entries

Exploit & PoC Resources

NO KNOWN EXPLOITNo public exploit confirmed at this time
Exploit-DB
Offensive Security exploit database
GitHub PoC Search
Community PoC repositories
Rapid7 / Metasploit
Metasploit module search
PacketStorm
Security advisories & exploits
NVD Detail
Official NIST entry
MITRE CVE
CVE Program entry
External links open in a new tab. Always verify in a controlled environment before use.

Official Patches & Advisories

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

All References (4)

→
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

Quick Facts

CVE IDCVE-2021-34148
CVSS Score6.5 / 10
SeverityMEDIUM
WeaknessNVD-CWE-noinfo
CISA KEVNo
Affected1 vendor(s)
PublishedSep 7, 2021

Related CVEs (NVD-CWE-noinfo)

CVE-2021-2177
10.0
CVE-2021-2244
10.0
CVE-2020-14701
10.0
CVE-2020-14606
10.0
CVE-2020-1467
10.0
CVE-2021-2248
10.0

Recommended Actions

  • →Apply vendor patches immediately
  • →Monitor CVE-2021-34148 in threat intel feeds
  • →Review IDS/IPS signatures for exploitation attempts
Data sourced from NVD (NIST), CISA KEV, and EPSS (FIRST). Analysis generated by CTIWATCH.COM. CVE data is provided under the NVD usage policy.
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