CVE-2021-3321

Name: CVE-2021-3321
Creator: NVD / NIST
Published: 2021-10-12T22:15:07.967+00:00
License: https://creativecommons.org/publicdomain/zero/1.0/

HIGHCVSS 8.8/10EPSS 0.74%

Last modified Jun 17, 2026

CVE-2021-3321 is a high-severity vulnerability rated 8.8/10 on the CVSS scale. Integer Underflow in Zephyr in IEEE 802154 Fragment Reassembly Header Removal. Zephyr versions >= >=2.4.0 contain Integer Overflow to Buffer Overflow (CWE-680). EPSS estimates a 0.74% chance of exploitation in the next 30 days.

Description

Integer Underflow in Zephyr in IEEE 802154 Fragment Reassembly Header Removal. Zephyr versions >= >=2.4.0 contain Integer Overflow to Buffer Overflow (CWE-680). For more information, see https://github.com/zephyrproject-rtos/zephyr/security/advisories/GHSA-w44j-66g7-xw99

Metrics

CVSS 3.1

8.8/10

CVSS:3.1/AV:A/AC:L/PR:N/UI:N/S:U/C:H/I:H/A:H

EPSS Probability

0.74%

49.8th percentile

Probability of exploitation in the next 30 days. Learn more

Weakness Enumeration

Affected Software

Vendor	Product	Versions
Zephyrproject	Zephyr	>= 2.4.0, < 2.5.0

References

http://github.com/zephyrproject-rtos/zephyr/security/advisories/GHSA-w44j-66g7-xw99Exploit, Patch, Third Party Advisory
http://github.com/zephyrproject-rtos/zephyr/security/advisories/GHSA-w44j-66g7-xw99Exploit, Patch, Third Party Advisory

Timeline

Published: Oct 12, 2021
Last Modified: Jun 17, 2026
Status: Modified

Frequently Asked Questions

What is CVE-2021-3321?

How severe is CVE-2021-3321?

CVE-2021-3321 has a CVSS score of 8.8/10 (HIGH severity). The EPSS model estimates a 0.74% probability of exploitation in the next 30 days.

How do I fix CVE-2021-3321?

Check the vendor references and advisories linked above for patched versions and mitigation guidance. You can also run a Strix scan to test if your systems are affected.

Are you affected by CVE-2021-3321?

Run a free Strix scan to check your systems for this vulnerability.

Scan your code now

Source: NVD / NIST