CVE-2021-3320

MEDIUMNVD 5.95.9—

5.9

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

CVSS v3: 5.9
EG Score: 5.9(medium)
EPSS: 56.6%
KEV: Not listed

Published

May 25, 2021

Last Modified

November 21, 2024

References (2)

vulnerabilities@zephyrprojecthttp://github.com/zephyrproject-rtos/zephyr/security/advisories/GHSA-27r3-rxch-2hm7
af854a3a-2127-422b-91ae-364da2661108http://github.com/zephyrproject-rtos/zephyr/security/advisories/GHSA-27r3-rxch-2hm7

Weakness Classification(2)

MITRE Common Weakness Enumeration — the root-cause categories this CVE belongs to.

Data Freshness Timeline

(refreshed 11× in last 7d / 19× in last 30d)

Every time one of our enrichment pipelines (NVD, MITRE cvelistV5, EPSS, CISA KEV, GHSA, OSV, vendor advisories) ran against this CVE. Most recent first.

2026-06-02 20:11 UTCepss_batch
2026-06-02 20:11 UTCepss_batch
2026-06-01 13:50 UTCepss_batch
2026-06-01 13:50 UTCepss_batch
2026-05-31 22:29 UTCepss_batch
2026-05-31 22:29 UTCepss_batch
2026-05-31 00:15 UTCepss_batch
2026-05-31 00:15 UTCepss_batch
2026-05-29 13:42 UTCepss_batch
2026-05-28 13:43 UTCepss_batch
2026-05-28 13:43 UTCepss_batch
2026-05-27 13:39 UTCepss_batch
2026-05-27 13:39 UTCepss_batch
2026-05-26 16:08 UTCEG score recompute
2026-05-26 13:42 UTCepss_batch
2026-05-26 13:42 UTCepss_batch
2026-05-26 07:17 UTCepss_batch
2026-05-26 07:17 UTCepss_batch
2026-05-26 07:17 UTCepss_batch

Frequently asked(5)

What is CVE-2021-3320?

CVE-2021-3320 is a medium vulnerability published on May 25, 2021. 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

When was CVE-2021-3320 disclosed?

CVE-2021-3320 was first published in the National Vulnerability Database on May 25, 2021, with the most recent update on November 21, 2024. EchelonGraph re-ingests CVE updates from NVD on a 2-hour cycle, so this page reflects the latest published state.

Is CVE-2021-3320 actively exploited?

CVE-2021-3320 is not currently on CISA's Known Exploited Vulnerabilities catalog. FIRST EPSS estimates a 56.6% percentile likelihood of exploitation in the next 30 days — higher percentiles indicate greater predicted risk.

What is the CVSS score of CVE-2021-3320?

CVE-2021-3320 has a CVSS v3 base score of 5.9 (NVD).

How do I remediate CVE-2021-3320?

Patch to the fixed version published by the affected vendor. Where vendor advisories exist for CVE-2021-3320, EchelonGraph cross-links them in the Vendor Advisories panel below — those typically contain the canonical remediation steps, fixed version numbers, and any vendor-specific mitigations.

Dependency Blast Radius

See which npm, PyPI, Go, and Maven packages are affected by CVE-2021-3320

Explore →

Is Your Infrastructure Affected by CVE-2021-3320?

EchelonGraph automatically scans your cloud infrastructure and maps CVE exposure using blast radius analysis.

Start Free Scan →Browse All CVEs

CVE-2021-3320

📅 Published

🔄 Last Modified

🔗 References (2)

Weakness Classification(2)

Data Freshness Timeline

❓ Frequently asked(5)

Dependency Blast Radius

Is Your Infrastructure Affected by CVE-2021-3320?

🔗 Related CVEs(same CWE)

Same CWE

Published

Last Modified

References (2)

Frequently asked(5)

Related CVEs(same CWE)