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A security researcher built a self-spreading worm that hides inside Word docs and hijacks Microsoft Copilot

Technology · en

A security researcher built a self-spreading worm that hides inside Word docs and hijacks Microsoft Copilot

The Decoder · Aug 1, 2026, 1:51 PM UTC

A security researcher has demonstrated a worm-like attack on Microsoft Copilot for Word: invisible prompt injections hidden in documents spread automatically into new files every time they're reused. Microsoft confirmed the issue but failed to fix it after 144 days and two attempts.…