What’s Vulnerable › Vulnerabilities

CVE-2026-85664: Chroma 1.5.9 Unbounded HNSW Index Parameters Memory Exhaustion

• Severity: high (CVSS 7.5 v3.1)
• Exploited in the wild: not listed in CISA KEV
• EPSS: 0.7% probability of exploitation in the next 30 days
• Public exploit or detection template: none known
• Published: 2026-09-04 · updated 2026-09-10
• Weakness: CWE-770

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

• chroma-core chroma: through 1.5.9

References

• 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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