Vulnerability record · CVE-2026-85664 · published 4 September 2026

CVE-2026-85664: Allocation without limits vulnerability

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.

8.7 CVSS 4.0 High EPSS 0.66% · top 50.5% CWE-770 · Allocation without limits Deferred

8.7CVSS 4.0 base score

0.66%EPSS exploitation probability, 30 days

NoNot in CISA KEV

0Affected product versions listed by NVD

5References

10 Sep 2026Last modified by NVD

Description

CVSS:4.0/AV:N/AC:L/AT:N/PR:N/UI:N/VC:N/VI:N/VA:H/SC:N/SI:N/SA:N/E:X/CR:X/IR:X/AR:X/MAV:X/MAC:X/MAT:X/MPR:X/MUI:X/MVC:X/MVI:X/MVA:X/MSC:X/MSI:X/MSA:X/S:X/AU:X/R:

References

Link	Tags
https://github.com/chroma-core/chroma
https://github.com/chroma-core/chroma/blob/1.5.9/rust/frontend/src/auth/mod.rs
https://github.com/chroma-core/chroma/blob/1.5.9/rust/types/src/hnsw_configuration.rs
https://github.com/chroma-core/chroma/issues/7225
https://www.vulncheck.com/advisories/chroma-1.5.9-unbounded-hnsw-index-parameters-memory-exhaustion

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Related vulnerabilities

Same products first, then exploited flaws of the same weakness class.

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Source: NIST National Vulnerability Database (record CVE-2026-85664), CISA KEV, FIRST EPSS (scores of 2026-09-26). This page is refreshed as NVD updates the record.