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CWE-191Weakness · CWE-191

CVE-2026-3172

HIGH · 8.1 CVSS v3.1 Published 2026-02-25
Mitigation only
No fix yet — a mitigation exists. There is no fixed release. A documented workaround reduces exposure in the meantime.
See remediation →
87/100
Remediation priority · High
Remotely reachable Zero-click

Official description Straight from the sourceThe vendor's or NVD's own wording, published unedited. Authoritative, but often terse — it says what broke, rarely what to do.

NVD · unedited
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.

Technical summary Written by usOur analysis, written from the advisory, the CVSS vector and the affected-version data. It adds context the advisory leaves out, and never invents facts that are not in the source.

dbcve analysis · high confidence

A buffer overflow vulnerability exists in pgvector's parallel HNSW (Hierarchical Navigable Small World) index building functionality, affecting versions 0.6.0 through 0.8.1. The overflow allows an authenticated database user to read adjacent memory contents, potentially exposing sensitive data from other database relations, or to trigger a denial of service by crashing the PostgreSQL server.

MitigationUpgrade pgvector to version 0.8.2 or later, which contains the security fix. After upgrading, rebuild any existing HNSW indexes to ensure they use the corrected code path.

Verify against the referenced sources before acting — the references below are authoritative for this CVE, this summary is not.

CVSS breakdown How the score is builtThe industry scoring standard. It rates how the flaw is reached, what it takes to exploit, and what an attacker gains — the score is derived from those, not the other way round.

From the vector
Attack vector
Network
Complexity
Low
Privileges
Low
User interaction
None
Scope
Unchanged
Confidentiality
High
Integrity
None
Availability
High

CVSS:3.1/AV:N/AC:L/PR:L/UI:N/S:U/C:H/I:N/A:H

Am I affected? How to checkSteps we derive from the advisory and the affected-version data, so you can decide whether this CVE reaches your setup. They are a guide, not a scan — your own configuration is the authority.

dbcve checks

Work through these to decide whether this CVE applies to you.

  1. Identify installed pgvector version
    Run SELECT extversion FROM pg_extension WHERE extname = 'pgvector'; or check your system's package manager for the pgvector package version
    Affected if Version is 0.6.0, 0.6.1, 0.7.0, 0.7.1, 0.7.2, 0.7.3, 0.7.4, 0.8.0, or 0.8.1 (any version from 0.6.0 through 0.8.1 inclusive)
  2. Verify HNSW index usage
    Query pg_indexes or pg_class to find indexes using the hnsw access method: SELECT indexname, indexdef FROM pg_indexes WHERE indexdef LIKE '%hnsw%';
    Affected if Any HNSW indexes exist in the database (the vulnerability triggers during HNSW index construction)
  3. Check for parallel HNSW index builds
    Review index definitions or application code for CREATE INDEX statements using both HNSW and the parallel option (mils_per_step parameter or explicit PARALLEL flag). Run EXPLAIN on existing HNSW indexes to see build parameters.
    Affected if Parallel building is enabled on HNSW indexes (the vulnerability specifically affects parallel HNSW index builds)
  4. Confirm authenticated user access
    Review database user permissions and application connection strings to determine if untrusted users have access to create indexes
    Affected if Untrusted or low-privilege authenticated users can create or rebuild indexes (the attacker needs authenticated database access to trigger the vulnerability)

You are affected if pgvector version is between 0.6.0 and 0.8.1 inclusive, and you have HNSW indexes that may be built or rebuilt with parallel processing enabled.

Generated from the published advisory. Verify against your own configuration.

Check your environment

Paste your version and any relevant configuration and it will be compared against the affected criteria above. Do not include secrets or credentials.

AI-assisted, checked against the advisory. Informational, not a guarantee.

Remediation Closing itWhat it takes to close this. Where a vendor fix exists we point at it; where none exists we say so plainly, and can build one. Effort estimates are scoped from the advisory, not from your codebase.

dbcve · scoped
Mitigation available No clean upgrade yet — mitigate in the meantime
Mitigation

Upgrade pgvector to version 0.8.2 or later, which contains the security fix. After upgrading, rebuild any existing HNSW indexes to ensure they use the corrected code path.

Recommended fix High confidence

pgvector 0.8.2 or later

  1. 1. Identify current pgvector version by running: SELECT extversion FROM pg_extension WHERE extname = 'vector';
  2. 2. Stop PostgreSQL service to ensure no active index builds during upgrade
  3. 3. Upgrade pgvector to version 0.8.2 or later using your package manager or compile from source (e.g., 'make install' from pgvector repository)
  4. 4. Verify the upgrade was successful: SELECT extversion FROM pg_extension WHERE extname = 'vector';
  5. 5. Rebuild any existing HNSW indexes that were created with parallel builds: ALTER INDEX index_name ALTER COLUMN vector SET (optimize = true);
  6. 6. Restart PostgreSQL service and verify database is functioning normally

Generated from the published advisory — verify against the referenced sources before acting.

Have this fixed Scoped from the published advisory
  • Consultation4.0 h
  • Implementation6.0 h
  • Testing6.0 h
  • Review / QA3.0 h
19.0 hours of engineering $3,320
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References Go to the primary sourcePrimary sources — vendor advisories, patches and trackers. Where our summary and a reference disagree, the reference wins.

Primary sources

Practitioner notes

Contributed

Peer-ranked notes from engineers who’ve handled CVE-2026-3172 in production — separate from our analysis above.

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What this is

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What belongs here
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  • Version or environment caveats, and links to real fixes
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