CVE-2019-20199 : Exploit Details and Defense Strategies

A vulnerability has been identified in versions 0.8.3 through 0.8.6 of the ezXML software library, leading to a NULL pointer dereference when executing strlen() on a NULL pointer.

Understanding CVE-2019-20199

This CVE involves incorrect memory management behavior in the ezXML library, specifically in the ezxml_decode function.

What is CVE-2019-20199?

CVE-2019-20199 is a vulnerability in ezXML versions 0.8.3 through 0.8.6 that can be exploited by parsing a specially crafted XML file, resulting in a NULL pointer dereference during strlen() execution.

The Impact of CVE-2019-20199

The vulnerability can be exploited to cause a denial of service (DoS) condition by crashing the application parsing the malicious XML file.

Technical Details of CVE-2019-20199

This section provides more technical insights into the vulnerability.

Vulnerability Description

The issue lies in the ezxml_decode function of ezXML versions 0.8.3 through 0.8.6, where incorrect memory handling leads to a NULL pointer dereference during strlen() execution.

Affected Systems and Versions

Affected Versions: 0.8.3 through 0.8.6 of ezXML
Systems using ezXML library versions within the specified range

Exploitation Mechanism

By crafting a malicious XML file and parsing it using the vulnerable ezXML library versions, an attacker can trigger the NULL pointer dereference.

Mitigation and Prevention

To address CVE-2019-20199, follow these mitigation strategies:

Immediate Steps to Take

Update ezXML to a patched version that addresses the memory management issue
Avoid parsing untrusted XML files with vulnerable ezXML versions

Long-Term Security Practices

Regularly update software libraries to patched versions
Implement input validation mechanisms to prevent malformed inputs

Patching and Updates

Apply patches or updates provided by the ezXML library maintainers to fix the vulnerability