CVE-2021-3455: Zephyrproject Zephyr

High severity, CVSS 7.5. EPSS: 1.1% chance of exploitation in the next 30 days.

Disconnecting L2CAP channel right after invalid ATT request leads freeze. Zephyr versions >= 2.4.0, >= 2.5.0 contain Use After Free (CWE-416). For more information, see https://github.com/zephyrproject-rtos/zephyr/security/advisories/GHSA-7g38-3x9v-v7vp

Affected products

• Zephyrproject Zephyr: from 2.4.0, before 2.6.0 (fixed in 2.6.0)

Published 2021-10-19. Last modified 2026-06-17.