CVE-2021-3455 : What You Need to Know

A detailed insight into CVE-2021-3455 that explores the vulnerability, impact, technical details, and mitigation strategies.

Understanding CVE-2021-3455

This section delves into the specifics of CVE-2021-3455, providing a comprehensive overview.

What is CVE-2021-3455?

The vulnerability involves disconnecting an L2CAP channel right after an invalid ATT request, resulting in a freeze. Zephyr versions >= 2.4.0, >= 2.5.0 are affected by a Use After Free issue (CWE-416).

The Impact of CVE-2021-3455

The CVSS score for this vulnerability is 4.3, with a base severity of MEDIUM. The attack complexity is LOW, and it requires no user interaction. The integrity and confidentiality of systems are unaffected, but there is a low impact on availability.

Technical Details of CVE-2021-3455

Explore the technical aspects of CVE-2021-3455 in this section.

Vulnerability Description

The vulnerability arises from disconnecting an L2CAP channel immediately after an invalid ATT request, leading to system freezing.

Affected Systems and Versions

Products by zephyrproject-rtos, specifically Zephyr versions >= 2.4.0 and >= 2.5.0, are impacted by this vulnerability.

Exploitation Mechanism

The vulnerability can be exploited by initiating the specific sequence, causing the system to freeze.

Mitigation and Prevention

Discover the steps to mitigate and prevent exploitation of CVE-2021-3455.

Immediate Steps to Take

Users are advised to update their Zephyr software to versions that contain fixes for the Use After Free vulnerability. Implementing restrictions on network access can also enhance security.

Long-Term Security Practices

Regularly updating and patching Zephyr software is crucial for maintaining system security. Additionally, implementing network security measures can reduce the risk of exploitation.

Patching and Updates

Stay informed about security advisories from zephyrproject-rtos and promptly apply patches and updates to safeguard your systems.