CVE-2019-19926 in SQLite
Summary
by MITRE
multiSelect in select.c in SQLite 3.30.1 mishandles certain errors during parsing, as demonstrated by errors from sqlite3WindowRewrite() calls. NOTE: this vulnerability exists because of an incomplete fix for CVE-2019-19880.
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Analysis
by VulDB Data Team • 03/16/2024
The vulnerability identified as CVE-2019-19926 represents a critical error handling flaw within the SQLite database engine version 3.30.1, specifically within the multiSelect functionality of the select.c module. This issue manifests when the system encounters certain parsing errors during the execution of sqlite3WindowRewrite() function calls, creating a scenario where the database engine fails to properly manage exceptional conditions that should be gracefully handled. The vulnerability is particularly concerning because it stems from an incomplete remediation of a previously identified security flaw, CVE-2019-19880, indicating a pattern of security gaps in the database engine's error processing mechanisms. This regression demonstrates the complexity of software security patching and the potential for introducing new vulnerabilities during the remediation process. The flaw resides in the core parsing logic that governs how SQLite handles window functions and multi-select operations, creating a potential attack surface where malicious input could trigger unexpected behavior.
The technical implementation of this vulnerability occurs within the select.c file where the SQLite engine attempts to process complex SQL queries involving window functions. When sqlite3WindowRewrite() encounters specific error conditions during query parsing, the multiSelect function fails to properly propagate or handle these errors, leading to potential memory corruption, unexpected program termination, or unauthorized access to database resources. This error handling failure creates a condition where the database engine may continue processing with inconsistent internal state, potentially allowing attackers to manipulate the parsing flow through carefully crafted SQL input. The vulnerability operates at the intersection of SQL parsing and window function evaluation, where the incomplete fix for CVE-2019-19880 left residual error paths that can be exploited. From a cybersecurity perspective, this represents a classic case of improper error handling that can lead to privilege escalation or data exposure, as the system's failure to properly manage exceptional conditions creates opportunities for malicious actors to gain unauthorized access to database resources.
The operational impact of CVE-2019-19926 extends beyond simple database corruption, potentially enabling attackers to execute arbitrary code or access sensitive data through carefully constructed SQL injection payloads. Systems utilizing SQLite 3.30.1 with window functions or complex multi-select queries become vulnerable to exploitation, particularly in environments where user input is processed through database queries. The vulnerability's presence in the parsing layer means that any application relying on SQLite for data processing could be compromised, with the attack surface expanding to include applications that perform window function operations or complex multi-select operations. This flaw aligns with CWE-704, which addresses improper error handling in software systems, and represents a significant concern for applications in the ATT&CK framework's execution and privilege escalation categories. Organizations using vulnerable SQLite versions face potential data breaches, system compromise, or denial of service conditions, as the vulnerability can be leveraged to disrupt database operations or extract confidential information through manipulation of the parsing error handling mechanisms.
Mitigation strategies for CVE-2019-19926 require immediate upgrading to SQLite version 3.31.0 or later, where the complete fix for both CVE-2019-19880 and CVE-2019-19926 has been implemented. Security administrators should conduct comprehensive vulnerability assessments to identify all systems running affected SQLite versions and prioritize remediation efforts accordingly. Additionally, implementing input validation controls and sanitization measures can provide temporary protection while awaiting the official security updates, though these measures do not address the root cause of the vulnerability. Organizations should also consider implementing database activity monitoring to detect potential exploitation attempts targeting this vulnerability, particularly focusing on unusual query patterns or error conditions that might indicate attempted exploitation. The vulnerability serves as a reminder of the importance of thorough regression testing during security patching processes, as incomplete fixes can create new attack vectors while attempting to resolve existing issues. System administrators should also review their database access controls and implement least privilege principles to minimize potential damage from successful exploitation attempts, ensuring that even if an attacker can trigger the vulnerability, they cannot easily escalate privileges or access sensitive data.