CVE-2026-85664 Chroma 1.5.9 Unbounded HNSW Index Parameters Memory Exhaustion
Unauthenticated attackers can cause denial of service in Chroma vector database by supplying unbounded HNSW index parameters that exhaust server memory.
- Exploited in the wild
- Not known
- Login needed
- Not needed
- Attackable
- Over the internet
- Victim action needed
- Not needed
- Fix
- None listed
What is CVE-2026-85664?
CVE-2026-85664 is a high-severity denial of service vulnerability in chroma-core chroma, published on 4 Sep 2026. An attacker can exploit it over the internet without logging in, with no action from the victim.
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.
Weakness: CWE-770
Which versions are affected by CVE-2026-85664?
How do I fix CVE-2026-85664?
No fix has been published for CVE-2026-85664 yet. Limit exposure of the affected software until one is available.
Upgrade, then put limits on request size, rate and nesting depth so one client cannot exhaust the service. More about Denial of service.
Is CVE-2026-85664 being exploited?
There is no known exploitation of CVE-2026-85664 in the wild and no public exploit code.
Sources
Also known as GHSA-3q9g-fh5w-hp67.