CVE-2021-45939: wolfSSL Wolfmqtt

Medium severity, CVSS 5.5. EPSS: 0.9% chance of exploitation in the next 30 days.

wolfSSL wolfMQTT 1.9 has a heap-based buffer overflow in MqttClient_DecodePacket (called from MqttClient_WaitType and MqttClient_Subscribe).

Affected products

• wolfSSL Wolfmqtt: version 1.9 only

Published 2022-01-01. Last modified 2026-06-17.