CVE-2021-31572: Amazon Freertos

Critical severity, CVSS 9.8. EPSS: 1.4% chance of exploitation in the next 30 days.

The kernel in Amazon Web Services FreeRTOS before 10.4.3 has an integer overflow in stream_buffer.c for a stream buffer.

Affected products

• Amazon Freertos: before 10.4.3 (fixed in 10.4.3)

Published 2021-04-22. Last modified 2026-06-17.