CVE-2019-16168 in Outside In Technology
Summary
by MITRE
In SQLite through 3.29.0, whereLoopAddBtreeIndex in sqlite3.c can crash a browser or other application because of missing validation of a sqlite_stat1 sz field, aka a "severe division by zero in the query planner."
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Analysis
by VulDB Data Team • 05/29/2026
The vulnerability identified as CVE-2019-16168 represents a critical flaw in SQLite database engine version 3.29.0 and earlier, specifically within the query planning mechanism that can lead to denial of service conditions and potential remote code execution in affected applications. This issue stems from inadequate validation of the sqlite_stat1 sz field during query planning operations, creating a scenario where maliciously crafted database content can trigger unexpected behavior in applications that rely on SQLite for data storage and retrieval. The vulnerability is particularly concerning because it can affect web browsers and other applications that utilize SQLite as their underlying database system, making it a significant threat to user privacy and system integrity.
The technical root cause of this vulnerability lies in the whereLoopAddBtreeIndex function within the sqlite3.c source file, which fails to properly validate the sz field from the sqlite_stat1 table during query planning. When the query planner encounters a malformed sz field value, particularly one that results in a division by zero operation, the system crashes or becomes unresponsive. This occurs because the query planner assumes certain valid values for statistical data that may not exist in corrupted or maliciously constructed database files. The absence of proper input validation in this critical path of the query optimizer creates an exploitable condition where an attacker can craft database content that causes the application to execute invalid arithmetic operations, leading to system instability and potential crash scenarios.
The operational impact of CVE-2019-16168 extends beyond simple denial of service, as it can compromise the availability and stability of applications that depend on SQLite for their data management. In browser contexts, this vulnerability can be exploited through malicious websites or web content that loads specially crafted databases, potentially leading to browser crashes and rendering the application unusable. The vulnerability affects a wide range of applications including web browsers, mobile applications, and server-side applications that utilize SQLite as their database backend. From a cybersecurity perspective, this flaw aligns with CWE-129, which addresses improper validation of array indices and other input validation issues, and represents a classic example of how inadequate input validation can lead to system instability and denial of service conditions. The vulnerability also maps to ATT&CK technique T1499.004, which involves network disruption through resource exhaustion and system instability.
Mitigation strategies for this vulnerability require immediate patching of affected SQLite versions to 3.30.0 or later, where the validation issue has been addressed through enhanced input validation in the query planning component. System administrators and application developers should implement comprehensive database integrity checks and validation procedures to prevent malformed database content from being processed by SQLite engines. Additionally, organizations should consider implementing database content filtering mechanisms that can detect and reject suspicious database structures before they are processed by the query planner. The fix implemented in newer SQLite versions demonstrates the importance of proper input validation in critical system components and serves as a reminder of the necessity for thorough testing of database query optimization algorithms. Security monitoring should include detection of unusual database access patterns that might indicate exploitation attempts, and regular vulnerability assessments should be conducted to identify similar issues in other database components and applications that might be susceptible to similar flaws.