CVE-2021-45932: 
Homebrew vulnerability analysis and mitigation

wolfSSL wolfMQTT 1.9 contains a heap-based buffer overflow vulnerability in the MqttDecodePublish function (called from MqttClientDecodePacket and MqttClient_HandlePacket). The vulnerability was discovered on September 1, 2021, and was later fixed in a subsequent release (OSS-Fuzz, OSV Report).

The vulnerability is a heap-based buffer overflow that occurs when writing 4 bytes beyond the allocated buffer in the MqttDecodePublish function. This function is called through the execution chain of MqttClientDecodePacket and MqttClient_HandlePacket. The issue has been assigned a HIGH severity rating according to the ecosystem-specific severity assessment (OSV Report).

A successful exploitation of this vulnerability could lead to memory corruption, potentially allowing an attacker to execute arbitrary code or cause the application to crash. The heap buffer overflow could potentially be used to write beyond the intended memory boundaries, which could compromise the system's security (OSV Report).

The vulnerability has been fixed in commit 84d4b53122e0fa0280c7872350b89d5777dabbb2 of the wolfMQTT repository. Users are advised to update to a version that includes this fix. The patch addresses the buffer overflow issue in the MqttDecode_Publish function (GitHub Patch).