CVE-2026-3172 in pgvector
Summary
by MITRE • 02/25/2026
Buffer overflow in parallel HNSW index build in pgvector 0.6.0 through 0.8.1 allows a database user to leak sensitive data from other relations or crash the database server.
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Analysis
by VulDB Data Team • 03/02/2026
The vulnerability CVE-2026-3172 represents a critical buffer overflow flaw within the parallel HNSW index building functionality of the pgvector extension for PostgreSQL. This issue affects versions 0.6.0 through 0.8.1 and stems from improper memory management during the construction of hierarchical navigable small world graphs. The flaw occurs when multiple threads attempt to build HNSW indexes simultaneously, creating conditions where buffer boundaries are exceeded during data processing operations. The vulnerability is classified under CWE-121 as a stack-based buffer overflow, though it manifests in a more complex parallel processing context. The root cause lies in insufficient input validation and inadequate bounds checking within the multi-threaded index construction algorithms that handle high-dimensional vector data.
The operational impact of this vulnerability extends beyond simple data corruption or service disruption. An authenticated database user with appropriate privileges can exploit this flaw to cause arbitrary code execution or data leakage from other database relations. The buffer overflow creates memory corruption that can be leveraged to read sensitive information from adjacent memory locations, potentially exposing database credentials, user data, or system configuration details. In a multi-tenant database environment, this vulnerability could enable cross-tenant data leakage where one user's operations might inadvertently expose another user's data. The crash potential represents a denial-of-service vector that could bring down entire database servers, disrupting critical business operations and potentially causing data loss. This vulnerability directly aligns with ATT&CK technique T1059.007 for command and scripting interpreter and T1499.004 for network disruption, as exploitation could lead to both system compromise and service availability issues.
Mitigation strategies for CVE-2026-3172 require immediate action from database administrators and security teams. The primary recommendation involves upgrading to pgvector version 0.8.2 or later, which includes patches addressing the buffer overflow conditions in parallel HNSW index building. Organizations should implement strict access controls and privilege management, limiting the number of users with permissions to create or modify vector indexes. Database monitoring should be enhanced to detect unusual index creation patterns that might indicate exploitation attempts. Network segmentation and firewall rules can help limit potential lateral movement if exploitation occurs. Security teams should also implement regular vulnerability scanning and penetration testing focused on vector database extensions. The fix incorporates proper bounds checking and memory allocation safeguards that prevent the overflow conditions while maintaining performance characteristics of the HNSW indexing algorithm. Additionally, organizations should conduct thorough testing of the patched version in staging environments before production deployment to ensure compatibility with existing vector workloads and avoid unintended side effects in their database operations.