2026-10-11 18:03 UTC

Follow-up research will determine whether document-borne prompt-injection worms can self-propagate through Copilot for Word across realistic users and require product-level containment.

state: expiredheat: lowuncertainty: highnovelscott: noneai-worms document-prompt-injection copilot-security

What is this?

The case concerns a reported prompt-injection technique in which hidden instructions embedded in documents processed by Microsoft Copilot for Word may cause agentic behavior to propagate through additional documents or users. The supplied snippets establish that Microsoft 365 Copilot processes potentially hostile file or email content, exposes an `XPIADetected` signal for cross-prompt injection, and has faced related attacks that bypass initial safeguards through follow-up instructions. However, they do not independently establish the claimed self-propagating Word worm, its behavior across realistic users, the identity of its researcher, or Microsoft/MSRC’s response, so those details remain based on the case’s thin disclosure summary.

Why it matters to Scott

No Scott wiki or radar intersection was found; the supplied material does not establish that this claim bears on a position, project, or tracked case of his.
queries asked of Scott's wikis
  • indirect prompt injection through documents and RAG
  • self-propagating agent actions and AI worms
  • trust boundaries for agent-generated documents
  • product-level containment for prompt injection
  • tainted-content tracking across agent workflows
  • Microsoft 365 Copilot security and document automation

Measured heat

no measured readings yet — the hourly heat pass fills this in

How the heat travelled

no chain yet — the hourly chain pass fills this in

Evidence (2) — ⭐ canonical anchor

sourceobjectauthorscorecomments
🟧 hnDocument-borne AI worms can self-propagate through Copilot for WordCanopy9560349267
🟧 echo.blog ⭐This is the original public disclosure. The author reports a coordinated disclosure with Microsoft/MSRC, describing hidden document instructHåkon Måløy——

Interpretation history

Decision trace