CVE-2021-28906 Explained : Impact and Mitigation

This CVE-2021-28906 article provides insights into a vulnerability identified in libyang <= v1.0.225, potentially leading to a crash due to unchecked values. Learn about the impact, technical details, and mitigation strategies.

Understanding CVE-2021-28906

CVE-2021-28906 is a vulnerability discovered in the read_yin_leaf() function within libyang <= v1.0.225. The issue arises from unchecked values, specifically regarding retval->ext[r], which under certain conditions can be NULL, causing a crash.

What is CVE-2021-28906?

The CVE-2021-28906 vulnerability originates from a lack of validation for the value of retval->ext[r] in the read_yin_leaf() function of libyang <= v1.0.225. This oversight can result in a crash when handling the flags associated with retval->ext[r].

The Impact of CVE-2021-28906

Exploitation of CVE-2021-28906 can lead to a denial of service (DoS) scenario or potential arbitrary code execution by malicious actors. The unchecked value can trigger a crash, disrupting the normal operation of the system.

Technical Details of CVE-2021-28906

The technical specifics of CVE-2021-28906 shed light on the vulnerability's description, affected systems, versions, and exploitation mechanisms.

Vulnerability Description

The vulnerability in libyang <= v1.0.225 arises from the lack of validation for the value of retval->ext[r]. This unchecked value, when NULL, can cause a crash during the processing of retval->ext[r]->flags.

Affected Systems and Versions

The affected systems include all instances of libyang up to version 1.0.225. Users operating on these versions are susceptible to the CVE-2021-28906 vulnerability.

Exploitation Mechanism

Malicious actors can exploit this vulnerability by manipulating the values of retval->ext[r] to be NULL, triggering a crash when the program attempts to access flags related to retval->ext[r].

Mitigation and Prevention

Mitigation strategies for CVE-2021-28906 involve immediate actions and long-term security measures to safeguard systems against potential attacks.

Immediate Steps to Take

It is recommended to implement the latest patches and updates provided by libyang to address the CVE-2021-28906 vulnerability. Additionally, monitor system logs for any unusual activities that could indicate exploitation attempts.

Long-Term Security Practices

Incorporate secure coding practices within the development lifecycle to prevent similar vulnerabilities from being introduced. Regular security audits and code reviews can help identify and resolve potential issues early on.

Patching and Updates

Stay informed about security advisories from libyang and promptly apply recommended patches and updates to ensure your systems are protected against known vulnerabilities.