PatchTheCVECVE-2021-34147: The Bluetooth Classic implementation in the Cypress WICED BT stack through 2.9.0 for CYW20735B1 does not prope
CVE-2021-34147 is a medium-severity flaw (CVSS 6.5) affecting wireless internet connectivity for embedded devices. Below: why it ranks where it does, which versions are affected, what to do, and the exact commands.
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.
Why this priority
- No elevated risk signals yet
A fixed release or distro patch exists.
Risk facts
| CVSS score | 6.5 (Medium) |
| Attack vector | Adjacent network |
| Attack complexity | Low |
| Privileges needed | None |
| User interaction | None |
| EPSS exploit chance | 0.6% (top 52%) |
| CISA exploited list | No |
| Published | 2021-09-07 |
| Last modified | 2026-06-17 |
Last updated 2026-06-17 · Sources: CVE Program, NVD, CISA KEV, EPSS and vendor advisories · How we score
Am I affected?
Timeline
- Published CVE record published
- Updated Record last modified
Scores and fixes here are computed automatically from those and other public sources. Confirm with the vendor advisory before changing production systems.
Quick answers
How do I fix CVE-2021-34147?
wireless internet connectivity for embedded devices: upgrade to newer than 2.9.0. Exact commands for each OS are on this page.
Is CVE-2021-34147 being exploited?
CVE-2021-34147 is not on the CISA Known Exploited Vulnerabilities list at the time of the last update. Check again, as this can change.
What does CVE-2021-34147 affect?
CVE-2021-34147 affects wireless internet connectivity for embedded devices. Severity is medium (CVSS 6.5). 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, allowin
How urgent is CVE-2021-34147?
Priority 35/100. No elevated risk signals yet.
Software pages
Related CVEs
- CVE-2021-34148 MEDIUM 6.5 UPGRADE The Bluetooth Classic implementation in the Cypress WICED BT stack through 2.9.0 for CYW20735B1 devices does n
- CVE-2021-34145 MEDIUM 5.3 UPGRADE The Bluetooth Classic implementation in the Cypress WICED BT stack through 2.9.0 for CYW20735B1 devices does n