CVE-2019-20393 : Security Advisory and Response

CVE-2019-20393 pertains to a double-free vulnerability in the function yyparse() in libyang versions before v1.0-r1. This vulnerability arises when an empty description is provided, potentially leading to a crash or the execution of arbitrary code if exploited.

Understanding CVE-2019-20393

This CVE involves a critical vulnerability in libyang that could be exploited to cause severe consequences.

What is CVE-2019-20393?

The CVE-2019-20393 vulnerability is a double-free vulnerability in the yyparse() function of libyang versions prior to v1.0-r1. It can be triggered when an empty description is supplied, making applications using libyang to interpret untrusted yang files vulnerable to potential crashes or arbitrary code execution.

The Impact of CVE-2019-20393

Exploitation of CVE-2019-20393 could lead to system crashes or unauthorized execution of arbitrary code, posing a significant risk to affected systems.

Technical Details of CVE-2019-20393

This section delves into the technical aspects of the CVE-2019-20393 vulnerability.

Vulnerability Description

The vulnerability in CVE-2019-20393 is a double-free vulnerability in the yyparse() function of libyang versions before v1.0-r1, triggered by an empty description input.

Affected Systems and Versions

Vendor: n/a
Product: n/a
Affected Versions: All versions prior to v1.0-r1

Exploitation Mechanism

The vulnerability can be exploited by providing an empty description, making applications using libyang to interpret untrusted yang files susceptible to crashes or arbitrary code execution.

Mitigation and Prevention

Protecting systems from CVE-2019-20393 requires immediate action and long-term security practices.

Immediate Steps to Take

Update libyang to version v1.0-r1 or later to mitigate the vulnerability.
Avoid interpreting untrusted yang files until the patch is applied.

Long-Term Security Practices

Regularly update software and libraries to the latest versions.
Implement input validation mechanisms to prevent malicious inputs.

Patching and Updates

Apply the security update provided by libyang to patch the vulnerability and ensure system security.