What is CVE-2021-3329?

CVE-2021-3329 is a critical-severity vulnerability in Zephyrproject Zephyr, classified under CWE-703. CVSS score: 9.6/10. Published 2023-02-26.

How severe is CVE-2021-3329?

Critical severity. CVSS v3 base score is 9.6 out of 10.

Vulnerability in Zephyrproject Zephyr

CVE-2021-3329

Lack of proper validation in HCI Host stack initialization can cause a crash of the bluetooth stack

Published 2023-02-26 · last modified 2026-06-17.

CVSS v3 metric

CVSS v3 base score 9.6 (Critical). Vector: CVSS:3.1/AV:A/AC:L/PR:N/UI:N/S:C/C:L/I:H/A:H.

EPSS exploit prediction

EPSS: 0.006 (48.5th percentile), scored 2026-10-19.

Very low probability of exploitation in the next 30 days; routine patching cadence is appropriate. 48th percentile — 48.5% of CVEs in the catalogue have a lower EPSS than this one. How to read EPSS.

EPSS over last 30 days · oldest: 0.006 · newest: 0.006 · change: 0.000

Affected products

Zephyrproject Zephyr — versions 2.4.0
Zephyrproject-Rtos Zephyr — versions unspecified

Weakness classification (CWE)

References

zephyrprojectsec.atlassian.net/browse/ZEPSEC-117 (Exploit, Issue Tracking, Vendor Advisory)

Frequently asked questions

What is CVE-2021-3329?: CVE-2021-3329 is a critical-severity vulnerability in Zephyrproject Zephyr, classified under CWE-703. CVSS score: 9.6/10. Published 2023-02-26.
How severe is CVE-2021-3329?: Critical severity. CVSS v3 base score is 9.6 out of 10.