CVE-2019-20391 Explained : Impact and Mitigation

CVE-2019-20391 is a vulnerability in libyang that can lead to an invalid memory access, potentially causing applications using libyang to crash.

Understanding CVE-2019-20391

This CVE identifies a specific flaw in libyang that can have serious consequences for applications utilizing this library.

What is CVE-2019-20391?

The function resolve_feature_value() in libyang before v1.0-r3 has a flaw that can result in an invalid memory access when an if-feature statement is used within a bit. This vulnerability has the potential to crash applications parsing untrusted yang files.

The Impact of CVE-2019-20391

The impact of this vulnerability is the potential for applications using libyang to crash due to an invalid memory access, which can be triggered by specific conditions within the library.

Technical Details of CVE-2019-20391

This section delves into the technical aspects of the CVE.

Vulnerability Description

The vulnerability lies in the resolve_feature_value() function in libyang before v1.0-r3, where an if-feature statement within a bit can lead to an invalid memory access.

Affected Systems and Versions

Vendor: n/a
Product: n/a
Versions: All versions are affected.

Exploitation Mechanism

The vulnerability can be exploited by utilizing an if-feature statement within a bit, triggering the invalid memory access.

Mitigation and Prevention

Protecting systems from CVE-2019-20391 is crucial to prevent crashes and potential security risks.

Immediate Steps to Take

Update libyang to version v1.0-r3 or later to mitigate the vulnerability.
Avoid parsing untrusted yang files until the library is patched.

Long-Term Security Practices

Regularly update software libraries to the latest versions to address known vulnerabilities.
Implement input validation mechanisms to prevent malicious inputs from triggering vulnerabilities.

Patching and Updates

Apply the security update provided by libyang to address CVE-2019-20391 and prevent potential crashes and security risks.