● Updated June 18, 2026SecurityResearch

MosaicLeaks: research agents can leak corporate secrets via ordinary web queries

Hugging Face introduces MosaicLeaks, a task and mitigation showing that research agents mixing private docs with web retrieval can leak sensitive facts through cumulative queries, and that PA‑DR training reduces leakage.

In detail

  • MosaicLeaks uses multi‑hop questions that interleave public and private info to model the mosaic effect
  • Training only for task performance increases leakage; Privacy‑Aware Deep Research (PA‑DR) cuts full‑information leakage from 34.0% to 9.9%
  • PA‑DR raises strict chain success (every hop correct) from 48.7% to 58.7%

Why it matters

Agents that combine local documents with external tools create a realistic leakage channel; reducing query‑based inference is critical for safe enterprise usage.

For you Monitor agent outbound queries, run mosaic‑style leakage tests on your agents, and consider adopting leak‑aware training or retrieval filters for agents handling sensitive data.

Updates

Hugging Face presents MosaicLeaks showing that research agents combining private docs with web retrieval can leak sensitive enterprise information through their query logs.

  • MosaicLeaks creates multi‑hop tasks mixing public and private info; many agents leaked private information in tests
  • Training solely for task performance increases leakage; Privacy‑Aware Deep Research (PA‑DR) raises strict chain success from 48.7% to 58.7%
  • PA‑DR lowers answer/full‑information leakage from 34.0% to 9.9%
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