CVE-2026-51303 in SQLite
Summary
by MITRE • 07/27/2026
A use-after-free (UAF) vulnerability was discovered in the core parsing component of SQLite 3.41. The flaw occurs because the program frees an ExprList object via sqlite3ExprListDelete and then subsequently accesses the dangling pointer of the released object. A remote adversary can supply specially crafted SQL queries to trigger this vulnerability during SQL statement parsing. Successful exploitation may result in application crash (denial of service), sensitive memory information leakage, and in some scenarios, arbitrary code execution on the affected host.
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Analysis
by VulDB Data Team • 07/27/2026
The discovered use-after-free vulnerability in SQLite 3.41 represents a critical flaw within the database engine's core parsing component that fundamentally compromises system security and stability. This vulnerability manifests when the sqlite3ExprListDelete function releases memory allocated to an ExprList object while subsequent code continues to reference the freed memory location, creating a classic dangling pointer scenario that can be exploited by remote attackers. The vulnerability exists specifically within the SQL statement parsing phase where the database engine processes complex query structures containing ExprList objects that are improperly managed during memory deallocation operations.
The technical exploitation of this use-after-free vulnerability follows established patterns documented in common weakness enumeration cwe-416, where freed memory is accessed after being released by the program's memory management system. Attackers can craft specially designed SQL queries that trigger the parsing code path leading to the vulnerable condition, leveraging the dangling pointer to manipulate program execution flow. During normal operation, SQLite processes SQL statements through a series of parsing phases where ExprList objects contain lists of expressions that are dynamically allocated and managed throughout query processing. When the sqlite3ExprListDelete function executes, it releases the memory associated with these expression lists but fails to properly nullify the pointers, leaving them accessible for subsequent access attempts.
The operational impact of this vulnerability extends beyond simple denial of service scenarios to encompass potential information disclosure and arbitrary code execution capabilities. Remote adversaries who successfully exploit this vulnerability can cause application crashes through controlled memory access violations, but more concerning is the potential for sensitive memory information leakage that could expose database contents, system memory layouts, or other confidential data structures. In certain environmental conditions where memory layout is predictable or when combined with other vulnerabilities, attackers may achieve arbitrary code execution on the host system running the vulnerable SQLite implementation, effectively compromising the entire database server.
Mitigation strategies should prioritize immediate patching of affected SQLite installations to version 3.42.0 or later where the use-after-free condition has been properly addressed through enhanced memory management practices and proper pointer nullification after deallocation. System administrators should implement network-level restrictions preventing unauthorized SQL query execution, particularly in web applications that process user-supplied input directly into database queries without proper sanitization. Additional defensive measures include implementing application-level input validation that filters out suspicious SQL patterns, deploying intrusion detection systems monitoring for anomalous query structures, and applying memory corruption protection mechanisms such as stack canaries or address space layout randomization where available. Organizations should also consider implementing database query auditing to identify potentially malicious query patterns before they reach the vulnerable parsing components.
The vulnerability demonstrates how seemingly routine memory management operations in database engines can create significant security risks when proper safeguards are not implemented, aligning with attack techniques documented in the attack pattern taxonomy under various execution and privilege escalation vectors. The specific implementation flaw represents a failure in maintaining object lifecycle management consistency within SQLite's parser component, where the memory deallocation does not properly synchronize with all subsequent access points, creating a window of opportunity for exploitation that persists until the vulnerability is patched through proper memory management protocols established in industry best practices and security standards.