CVE-2026-51300 in SQLite
Summary
by MITRE • 07/27/2026
A use-after-free vulnerability exists in the expression parsing and memory management logic of SQLite 3.41. After invoking sqlite3ExprDelete to release an expression object, the program still retains the dangling pointer and subsequently accesses member fields of the already freed memory. By constructing malicious SQL queries, a remote attacker can trigger invalid memory access, leading to application crash and sensitive memory information leakage.
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Analysis
by VulDB Data Team • 07/27/2026
The vulnerability under examination represents a classic use-after-free condition within SQLite version 3.41 that stems from inadequate memory management during expression parsing operations. This flaw resides in the core database engine's handling of expression objects where the sqlite3ExprDelete function fails to properly nullify references to freed memory structures, creating a scenario where subsequent code paths attempt to access deallocated resources. The technical implementation demonstrates a fundamental failure in memory lifecycle management where the program logic does not adequately enforce pointer invalidation after object deletion, violating established principles of safe memory handling practices.
The operational impact of this vulnerability extends beyond simple application instability to encompass potential information disclosure and denial of service conditions. When an attacker crafts malicious SQL queries that trigger the specific code path involving expression deletion, the dangling pointer access can result in unpredictable behavior including segmentation faults, heap corruption, or memory leakage that exposes sensitive data from adjacent memory regions. This type of vulnerability falls under CWE-416 which specifically addresses use-after-free conditions, and aligns with ATT&CK technique T1059.008 for abuse of command and scripting interpreters where database engines serve as attack vectors through crafted input sequences.
The exploitation mechanism relies on the attacker's ability to construct SQL statements that force SQLite to process expression objects through the vulnerable deletion sequence, creating a race condition between memory deallocation and subsequent access operations. This vulnerability represents a critical threat to database integrity and system availability since it can be triggered remotely through standard database query interfaces without requiring elevated privileges or specialized attack vectors. The memory management flaw demonstrates poor defensive programming practices where proper nullification of freed pointers should occur immediately after deletion operations to prevent any possibility of subsequent dereference.
Mitigation strategies for this vulnerability require immediate patching of SQLite installations to version 3.42.0 or later where the memory management logic has been corrected to properly invalidate dangling pointers. System administrators should implement comprehensive monitoring for unusual database access patterns that might indicate exploitation attempts, while application developers need to ensure proper input validation and sanitization of all SQL queries. The fix implemented in the patched versions addresses the root cause by ensuring that expression object references are nullified immediately upon deletion, preventing any subsequent memory access attempts and eliminating the possibility of information disclosure through heap corruption attacks. Organizations should also consider implementing database query auditing mechanisms to detect potentially malicious SQL constructs that might trigger similar memory management vulnerabilities in other components of their database infrastructure.