---
id: CVE-2026-85664
title: >-
  Chroma 1.5.9 fails to validate maximum bounds on HNSW index parameters
  max_neighbors, ef_construction, and ef_search in collection-create requests
summary: >-
  Chroma 1.5.9 fails to validate maximum bounds on HNSW index parameters
  max_neighbors, ef_construction, and ef_search in collection-create requests.
  Unauthenticated attackers can supply arbitrarily large parameter values to
  exhaust server…
severity: high
cvss: 7.5
cvssVector: 'CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:N/I:N/A:H'
cwe:
  - CWE-770
  - CWE-1284
vendor: chroma-core
product: chroma
affected:
  - chroma <= 1.5.9
published: '2026-09-04'
updated: '2026-09-10'
sourceUpdated: '2026-09-10T16:18:00.510'
source: NVD
sourceUrl: 'https://nvd.nist.gov/vuln/detail/CVE-2026-85664'
references:
  - url: 'https://github.com/chroma-core/chroma'
    label: disclosure@vulncheck.com
  - url: >-
      https://github.com/chroma-core/chroma/blob/1.5.9/rust/frontend/src/auth/mod.rs
    label: disclosure@vulncheck.com
  - url: >-
      https://github.com/chroma-core/chroma/blob/1.5.9/rust/types/src/hnsw_configuration.rs
    label: disclosure@vulncheck.com
  - url: 'https://github.com/chroma-core/chroma/issues/7225'
    label: disclosure@vulncheck.com
  - url: >-
      https://www.vulncheck.com/advisories/chroma-1.5.9-unbounded-hnsw-index-parameters-memory-exhaustion
    label: disclosure@vulncheck.com
  - url: >-
      https://security.access.redhat.com/data/csaf/v2/vex/2026/cve-2026-85664.json
  - url: 'https://access.redhat.com/security/cve/CVE-2026-85664'
  - url: 'https://bugzilla.redhat.com/show_bug.cgi?id=2531492'
  - url: 'https://www.cve.org/CVERecord?id=CVE-2026-85664'
  - url: 'https://nvd.nist.gov/vuln/detail/CVE-2026-85664'
tags:
  - nvd
  - cve.org
  - csaf
  - vex
  - red-hat
ssvc:
  exploitation: none
  automatable: 'yes'
  technicalImpact: partial
  timestamp: '2026-09-10T14:23:02.954885Z'
epss: 0.00366
epssPercentile: 0.30466
ingestedAt: '2026-09-10T15:53:17.107Z'
---

## Overview

Chroma 1.5.9 fails to validate maximum bounds on HNSW index parameters max_neighbors, ef_construction, and ef_search in collection-create requests. Unauthenticated attackers can supply arbitrarily large parameter values to exhaust server memory and cause denial of service during index compaction.

## Remediation

Refer to the linked advisories for vendor-supplied fixes and affected version ranges.

## Vendor advisories

- **Red Hat VEX** · Important · updated 2026-09-11 · [vex](https://security.access.redhat.com/data/csaf/v2/vex/2026/cve-2026-85664.json)