LLM09:2026 Vector and Embedding Weaknesses

Why it matters

The retrieval layer decides what the model sees; without access control, poisoned or cross-tenant documents can be retrieved, and embeddings can sometimes be inverted to recover their source text.

How to prevent it

Enforce tenant and user permissions in the retrieval query itself, not after the model answers.
Validate documents and record their source before embedding them.
Protect vector stores like any database that holds the original data, with access control, encryption and logging.

Guides on this site

Main subject · Guide

Keep retrieval inside the user’s data boundary

Carry document permissions through ingestion, retrieval, caching and citations so a model never receives another tenant’s records.

Practice

RAG access control lab: Stop a retriever from returning another tenant’s documents · Browser lab
Enforce retrieval and tool boundaries across crashes · Local project

References

List data from the publisher. A guide is listed as the main subject when the weakness or risk is what the guide is about, and as covering it when a dedicated section or worked example addresses it.