CVE-2021-3321: Zephyrproject Zephyr

High severity, CVSS 8.8. EPSS: 0.8% chance of exploitation in the next 30 days.

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

Affected products

• Zephyrproject Zephyr: from 2.4.0, before 2.5.0 (fixed in 2.5.0)

Published 2021-10-12. Last modified 2026-06-17.