CVE-2021-28166 Explained : Impact and Mitigation

A vulnerability has been identified in Eclipse Mosquitto versions 2.0.0 to 2.0.9, which could allow for a NULL pointer dereference under specific conditions when a crafted CONNACK message is sent by an authenticated client.

Understanding CVE-2021-28166

This section delves into the details of the CVE-2021-28166 vulnerability.

What is CVE-2021-28166?

CVE-2021-28166 is a security vulnerability found in Eclipse Mosquitto versions 2.0.0 to 2.0.9, where a NULL pointer dereference occurs when a specifically crafted CONNACK message is transmitted by an authenticated MQTT v5 client to the broker.

The Impact of CVE-2021-28166

The vulnerability scored a CVSS base score of 6.5, with a HIGH impact on availability. Although the attack complexity is low, exploitation may lead to a NULL pointer dereference.

Technical Details of CVE-2021-28166

This section provides technical insights into CVE-2021-28166.

Vulnerability Description

The issue arises in Eclipse Mosquitto versions 2.0.0 to 2.0.9 due to a NULL pointer dereference caused by a crafted CONNACK message.

Affected Systems and Versions

Eclipse Mosquitto versions 2.0.0 to 2.0.9 are impacted by this vulnerability, particularly when an authenticated MQTT v5 client interacts with the broker.

Exploitation Mechanism

If an authenticated client connected with MQTT v5 sends a maliciously crafted CONNACK message to the broker, it triggers a NULL pointer dereference in versions 2.0.0 to 2.0.9.

Mitigation and Prevention

In this section, we explore measures to mitigate and prevent the exploitation of CVE-2021-28166.

Immediate Steps to Take

Users are advised to update Eclipse Mosquitto to versions beyond 2.0.9 or apply official fixes to address the vulnerability promptly.

Long-Term Security Practices

Practicing secure coding, ensuring proper input validation, and staying informed about security updates are key for long-term security.

Patching and Updates

Regularly checking for security patches and promptly applying updates for Eclipse Mosquitto can help prevent exploitation of known vulnerabilities.