CVE-2019-19923 : Security Advisory and Response

SQLite 3.30.1's function flattenSubquery in the select.c file has a vulnerability when using SELECT DISTINCT with a LEFT JOIN, leading to a NULL pointer dereference or incorrect results.

Understanding CVE-2019-19923

What is CVE-2019-19923?

CVE-2019-19923 is a vulnerability in SQLite 3.30.1 that affects the function flattenSubquery in the select.c file, specifically when using SELECT DISTINCT with a LEFT JOIN involving a view.

The Impact of CVE-2019-19923

This vulnerability can result in a NULL pointer dereference or produce incorrect query results, potentially leading to system instability or incorrect data processing.

Technical Details of CVE-2019-19923

Vulnerability Description

The issue arises from mishandling certain scenarios involving SELECT DISTINCT with a LEFT JOIN where the right-hand side is a view, causing a NULL pointer dereference or incorrect results.

Affected Systems and Versions

Product: SQLite
Version: 3.30.1

Exploitation Mechanism

The vulnerability can be exploited by crafting SQL queries that trigger the flawed handling of SELECT DISTINCT with a LEFT JOIN and a view, leading to the mentioned issues.

Mitigation and Prevention

Immediate Steps to Take

Apply patches provided by SQLite to address the vulnerability.
Monitor SQLite's security advisories for updates and apply them promptly.

Long-Term Security Practices

Regularly update SQLite to the latest secure versions.
Implement secure coding practices to avoid SQL injection and other vulnerabilities.

Patching and Updates

Stay informed about security updates from SQLite and apply them as soon as they are released.