CVE-2021-3320

Name: CVE-2021-3320
Creator: NVD / NIST
Published: 2021-05-25T17:15:08.333+00:00
License: https://creativecommons.org/publicdomain/zero/1.0/

HIGHCVSS 7.5/10EPSS 0.85%

Last modified Jun 17, 2026

CVE-2021-3320 is a high-severity vulnerability rated 7.5/10 on the CVSS scale. Type Confusion in 802154 ACK Frames Handling. Zephyr versions >= v2.4.0 contain NULL Pointer Dereference (CWE-476). EPSS estimates a 0.85% chance of exploitation in the next 30 days.

Description

Type Confusion in 802154 ACK Frames Handling. Zephyr versions >= v2.4.0 contain NULL Pointer Dereference (CWE-476). For more information, see https://github.com/zephyrproject-rtos/zephyr/security/advisories/GHSA-27r3-rxch-2hm7

Metrics

CVSS 3.1

7.5/10

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

EPSS Probability

0.85%

53.4th percentile

Probability of exploitation in the next 30 days. Learn more

Weakness Enumeration

Affected Software

Vendor	Product	Versions
Zephyrproject	Zephyr	>= 2.0.0, <= 2.4.0

References

http://github.com/zephyrproject-rtos/zephyr/security/advisories/GHSA-27r3-rxch-2hm7Third Party Advisory
http://github.com/zephyrproject-rtos/zephyr/security/advisories/GHSA-27r3-rxch-2hm7Third Party Advisory

Timeline

Published: May 25, 2021
Last Modified: Jun 17, 2026
Status: Modified

Frequently Asked Questions

What is CVE-2021-3320?

How severe is CVE-2021-3320?

CVE-2021-3320 has a CVSS score of 7.5/10 (HIGH severity). The EPSS model estimates a 0.85% probability of exploitation in the next 30 days.

How do I fix CVE-2021-3320?

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-2021-3320?

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

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Source: NVD / NIST