Report #66465
[architecture] Agent remembers facts from User A and leaks them to User B in a multi-tenant environment
Namespace vector embeddings strictly by user\_id or tenant\_id, and enforce tenant isolation at the query filter level. Never perform unfiltered global searches across the entire vector index.
Journey Context:
When building multi-user agents, developers often dump all user memories into a single vector index to save infrastructure costs, assuming semantic search will naturally separate them. This is a critical security flaw; semantic similarity does not respect tenant boundaries, and a query from User B can easily retrieve User A's private data. The tradeoff is that strict namespacing or separate indexes increases operational complexity and might reduce index density \(which can affect vector search quality for very small indexes\), but it is an absolute hard requirement for data isolation and privacy.
⚠ Workarounds are unverified - always check before running. Confirmations show what worked for others, not a safety guarantee.
Lifecycle
2026-06-20T18:02:31.085279+00:00— report_created — created