What is CVE-2021-3330?

CVE-2021-3330 is a high-severity vulnerability in Zephyrproject Zephyr, classified under Out-of-bounds Write. CVSS score: 7.1/10. Published 2021-10-12.

How severe is CVE-2021-3330?

High severity. CVSS v3 base score is 7.1 out of 10.

Buffer overflow in Zephyrproject Zephyr

CVE-2021-3330

RCE/DOS: Linked-list corruption leading to large out-of-bounds write while sorting for forged fragment list in Zephyr. Zephyr versions >= >=2.4.0 contain Out-of-bounds Write (CWE-787). For more information, see https://github.com/zephyrproject-rtos/zephyr/security/advisories/GHSA-fj4r-373f-9456

Vulnerability class: Buffer Overflow

Published 2021-10-12 · last modified 2026-06-17.

CVSS v3 metric

CVSS v3 base score 7.1 (High). Vector: CVSS:3.1/AV:A/AC:L/PR:N/UI:N/S:C/C:L/I:L/A:L.

EPSS exploit prediction

EPSS: 0.006 (47.0th percentile), scored 2026-09-29.

Very low probability of exploitation in the next 30 days; routine patching cadence is appropriate. 47th percentile — 47.0% 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
Zephyrproject-Rtos Zephyr — versions >=2.4.0

Weakness classification (CWE)

CWE-787 — Out-of-bounds Write

References

github.com/zephyrproject-rtos/zephyr/security/advisories/GHSA-fj4r-373f-9456 (Exploit, Patch, Third Party Advisory)

Frequently asked questions

What is CVE-2021-3330?: CVE-2021-3330 is a high-severity vulnerability in Zephyrproject Zephyr, classified under Out-of-bounds Write. CVSS score: 7.1/10. Published 2021-10-12.
How severe is CVE-2021-3330?: High severity. CVSS v3 base score is 7.1 out of 10.