CVE-2021-3431 Explained : Impact and Mitigation

This article provides detailed information about CVE-2021-3431, a vulnerability impacting Zephyr versions >= v2.5.0 related to an assertion failure on repeated LL_FEATURE_REQ.

Understanding CVE-2021-3431

CVE-2021-3431 is a vulnerability in Zephyr versions >= v2.5.0 that leads to an assertion reachable with repeated LL_FEATURE_REQ, identified as Reachable Assertion (CWE-617).

What is CVE-2021-3431?

The vulnerability in Zephyr versions >= v2.5.0 allows an attacker to trigger an assertion failure by exploiting repeated LL_FEATURE_REQ scenarios, presenting a Reachable Assertion (CWE-617) risk.

The Impact of CVE-2021-3431

With a CVSS v3.1 base score of 4.3 (Medium severity), this vulnerability poses a threat of low availability impact, affecting adjacent network attack vectors but requiring no user interaction or additional privileges.

Technical Details of CVE-2021-3431

The technical details of CVE-2021-3431 include:

Vulnerability Description

The vulnerability arises from an assertion reachable with repeated LL_FEATURE_REQ in Zephyr versions >= v2.5.0.

Affected Systems and Versions

Zephyr versions above v2.5.0 are impacted by this vulnerability.

Exploitation Mechanism

Attackers can exploit this vulnerability through scenarios involving repeated LL_FEATURE_REQ, triggering an assertion failure.

Mitigation and Prevention

To address CVE-2021-3431, consider the following mitigation strategies:

Immediate Steps to Take

Upgrade affected Zephyr versions to a secure release.
Monitor security advisories from Zephyr for patch updates.

Long-Term Security Practices

Implement secure coding practices to prevent assertion failures.
Regularly update Zephyr components to mitigate known vulnerabilities.

Patching and Updates

Apply patches and updates released by Zephyr to address the vulnerability effectively.