CVE-2021-3329
DOS: Incorrect handling of the initial HCI ACL_MTU handshake packet leads to crash of bluetooth host layer
Lack of proper validation in HCI Host stack initialization can cause a crash of the bluetooth stack
Attack profile
How easy it is to exploit
- Attack vector
- Adjacent network
- Complexity
- Low
- Privileges needed
- None
- User interaction
- None
What an attacker can affect
- Confidentiality
- Low
- Integrity
- High
- Availability
- High
Exploit likelihood
What each source reports
CVE List Score used
DOS: Incorrect handling of the initial HCI ACL_MTU handshake packet leads to crash of bluetooth host layer
Lack of proper validation in HCI Host stack initialization can cause a crash of the bluetooth stack
- Record
CVE-2021-3329- CVSS 3.1
- 9.6 Critical
CVSS:3.1/AV:A/AC:L/PR:N/UI:N/S:C/C:L/I:H/A:H - Weakness
- CWE-703
- Updated
- 2026-11-02
EUVDEUVD-2021-26660
Lack of proper validation in HCI Host stack initialization can cause a crash of the bluetooth stack
- Record
EUVD-2021-26660- CVSS 3.1
- 9.6 Critical
CVSS:3.1/AV:A/AC:L/PR:N/UI:N/S:C/C:L/I:H/A:H - Updated
- 2026-11-02
GitHub AdvisoriesGHSA-gmxc-973j-62f2
Lack of proper validation in HCI Host stack initialization can cause a crash of the bluetooth stack
Lack of proper validation in HCI Host stack initialization can cause a crash of the bluetooth stack
- Record
GHSA-gmxc-973j-62f2- CVSS 3.1
- 6.5 Medium
CVSS:3.1/AV:A/AC:L/PR:N/UI:N/S:U/C:N/I:N/A:H - Weakness
- CWE-665
- Updated
- 2026-11-02
NVD
Lack of proper validation in HCI Host stack initialization can cause a crash of the bluetooth stack
- Record
CVE-2021-3329- CVSS 3.1
- 9.6 Critical
CVSS:3.1/AV:A/AC:L/PR:N/UI:N/S:C/C:L/I:H/A:H - CVSS 3.1
- 6.5 Medium
CVSS:3.1/AV:A/AC:L/PR:N/UI:N/S:U/C:N/I:N/A:H - Weakness
- CWE-703, CWE-665
- Updated
- 2026-11-02
Affected products
History
| Recorded | Changed | Sources |
|---|---|---|
| first indexed | CVE List, EUVD, GitHub Advisories, NVD |
Dates are when Every CVE recorded each change. Upstream dates may differ.
In short
CVE-2021-3329 is a critical vulnerability (CVSS 9.6) in Zephyrproject Zephyr, published February 26, 2023. No source lists public exploit code. EPSS puts the chance of exploitation in the next 30 days at 0.62%, the 50th percentile. No source names a fixed version.