CVE-2026-3172

High

Published: 25 February 2026

Published

25 February 2026

Modified

15 April 2026

KEV Added

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Patch

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CVSS Score v3.1 8.1 CVSS:3.1/AV:N/AC:L/PR:L/UI:N/S:U/C:H/I:N/A:H

EPSS Score 0.0026 17.5th percentile

Risk Priority 55 floored blend · peak EPSS

Summary

CVE-2026-3172 is a high-severity Wrap or Wraparound (CWE-191) vulnerability. Its CVSS base score is 8.1 (High).

Operationally, exploitation aligns with the MITRE ATT&CK technique Exploit Public-Facing Application (T1190); ranked at the 17.5th percentile by exploit likelihood (below the median); it is not currently listed in the CISA KEV catalog.

This vulnerability is AI-related — categorised as Similarity Search; in the Privacy and Disclosure risk domain.

The strongest mitigations our analysis identified are NIST 800-53 SI-2 (Flaw Remediation) and CM-6 (Configuration Settings).

Deeper analysis

CVE-2026-3172 is a buffer overflow vulnerability in the parallel HNSW index build feature of the pgvector PostgreSQL extension, affecting versions 0.6.0 through 0.8.1. pgvector provides vector similarity search capabilities, often used for AI/ML workloads involving embedding storage and retrieval. The flaw arises from inadequate bounds checking during parallel Hierarchical Navigable Small World (HNSW) index construction, potentially leading to memory corruption as mapped to CWE-191 (Integer Underflow or Wraparound) and CWE-787 (Out-of-bounds Write). It was published on 2026-02-25 with a CVSS v3.1 base score of 8.1 (AV:N/AC:L/PR:L/UI:N/S:U/C:H/I:N/A:H).

A database user with low privileges can exploit this remotely over the network without user interaction. By triggering the vulnerable parallel HNSW index build—such as via CREATE INDEX in parallel mode—they can leak sensitive data from other relations (high confidentiality impact) or crash the PostgreSQL server (high availability impact), resulting in denial of service.

The GitHub issue at https://github.com/pgvector/pgvector/issues/959 serves as the primary reference, documenting the vulnerability and likely including patch details or mitigation guidance from the pgvector maintainers.

This issue holds relevance for AI/ML deployments relying on pgvector for vector databases, but no real-world exploitation is noted in the available information.

EU & UK References

🇪🇺 ENISA EUVD: EUVD-2026-8743

Vulnerability details

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.

CWE(s): CWE-191 CWE-787

AI Security AnalysisAI

AI Category: Similarity Search
Risk Domain: Privacy and Disclosure
OWASP Top 10 for LLMs 2025: None mapped
Classification Reason: Matched keywords: pgvector

Related Threats

MITRE ATT&CK Enterprise TechniquesAI

T1190 Exploit Public-Facing Application Initial Access

Adversaries may attempt to exploit a weakness in an Internet-facing host or system to initially access a network.

attack.mitre.org →

T1213.006 Databases Collection

Adversaries may leverage databases to mine valuable information.

attack.mitre.org →

T1499.004 Application or System Exploitation Impact

Adversaries may exploit software vulnerabilities that can cause an application or system to crash and deny availability to users.

attack.mitre.org →

Why these techniques?

Buffer overflow in exposed pgvector/Postgres extension directly enables remote exploitation of public-facing app (T1190), unauthorized data leaks from database relations (T1213.006), and DoS via targeted application crash (T1499.004).

Confidence: HIGH · MITRE ATT&CK Enterprise v19.0