Vulnerability · Published Sep 4, 2026 · Assigned by VulnCheck
CVE-2026-85664Chroma 1.5.9 Unbounded HNSW Index Parameters Memory Exhaustion
High 7.5
In plain English
A high-severity resource allocation without limits in chroma from chroma-core. There are no confirmed reports of exploitation so far. The chance it is exploited in the next 30 days is estimated at 0.7% (higher than 52% of all known vulnerabilities).
Severity (CVSS 3.1)7.5High
Exploit odds (30 days)0.7%top 48.3% of all CVEs
Exploited in the wildNo reportsCISA SSVC: none
Attack toolingNoneno public tooling known
Official description
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.
Affected products (as reported)
| Vendor | Product | Versions |
|---|---|---|
| chroma-core | chroma | 0 – through 1.5.9 |
Weakness: CWE-770 · Vector: CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:N/I:N/A:H
References
- GitHub Issue #7225 issue-tracking
- https://github.com/chroma-core/chroma product
- https://github.com/chroma-core/chroma/blob/1.5.9/rust/types/src/hnsw_configuration.rs technical-description
- https://github.com/chroma-core/chroma/blob/1.5.9/rust/frontend/src/auth/mod.rs technical-description
- VulnCheck Advisory: Chroma 1.5.9 Unbounded HNSW Index Parameters Memory Exhaustion third-party-advisory