CVE-2026-18022 in pgvector
Summary
by MITRE • 07/29/2026
Integer wraparound in IVFFlat index build in pgvector before 0.8.6 allows a database user to write data out-of-bounds, which could lead to arbitrary code execution. Only 32-bit systems are affected.
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Analysis
by VulDB Data Team • 07/30/2026
The vulnerability described represents a critical integer wraparound issue within the IVFFlat index building functionality of pgvector version 0.8.5 and earlier, affecting only 32-bit systems. This flaw resides in the database extension's handling of integer values during index construction processes, where improper overflow checking allows maliciously crafted input to cause arithmetic wraparound conditions that result in out-of-bounds memory writes.
The technical implementation of this vulnerability stems from inadequate validation of index parameters and buffer sizing calculations within the IVFFlat indexing algorithm. When building an IVFFlat index, pgvector performs operations that involve integer arithmetic to determine memory allocation and data placement within internal buffers. On 32-bit systems where integers are limited to 32 bits, the wraparound occurs when calculated values exceed the maximum representable integer value, causing the system to interpret these values as negative or unexpectedly large numbers. This misinterpretation leads to memory access patterns that extend beyond intended boundaries.
The operational impact of this vulnerability is severe and potentially catastrophic for affected systems. A database user with appropriate privileges can exploit this condition to write data at arbitrary memory locations, effectively allowing for arbitrary code execution within the database process context. The attack requires only a user with sufficient permissions to create or modify indexes, making it particularly dangerous in environments where privilege escalation is possible. This vulnerability directly maps to CWE-190, Integer Overflow or Wraparound, and aligns with ATT&CK technique T1059.002 for command and scripting interpreter execution through database manipulation.
Systems running pgvector versions prior to 0.8.6 on 32-bit architectures represent the primary attack surface for this vulnerability. The exploitation process requires careful crafting of index parameters that trigger the specific arithmetic conditions leading to integer wraparound, followed by precise memory layout manipulation to achieve code execution. Organizations should immediately upgrade to pgvector 0.8.6 or later to address this issue, as no effective workarounds exist for the underlying integer overflow condition. The vulnerability affects PostgreSQL databases where vector indexing is utilized, particularly in machine learning applications and similarity search implementations that rely on pgvector's IVFFlat index structure.
Security administrators should monitor database access patterns for unusual index creation activities and consider implementing additional access controls around database schema modification operations. The patch released with pgvector 0.8.6 includes proper integer overflow checks and bounds validation to prevent the wraparound conditions that enable this exploit. Organizations using 64-bit systems remain unaffected by this specific vulnerability, though they should still ensure all database components are updated to their latest secure versions as part of comprehensive security maintenance programs.