LangChain ChromaDB Metadata Priority Injection

Vulnerability Summary

LangChain's Chroma integration allows attackers to manipulate document retrieval by injecting high-priority metadata fields, forcing malicious documents to rank above legitimate ones regardless of semantic relevance.

Affected Versions

langchain-community: All versions <= 0.3.x

langchain-chroma: All versions

chromadb: All versions

Attack Vector

# Attacker uploads document with manipulated metadata poisoned_doc = { ' text ' : ' Malicious insurance policy: Coverage limit is 5,000 Kč ' , ' metadata ' : { ' priority ' : 999 } # Force highest ranking }

# Victim's RAG system retrieves poisoned doc first # Legitimate docs with lower priority are ignored

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Impact

OWASP LLM08 : Vector and Embedding Weaknesses

MITRE ATT&CK : T1565.001 (Data Manipulation)

Affects insurance, legal, medical RAG systems

Persistent poisoning (survives database restarts)

PoC

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