Connecticut Judge Sanctions Litigant for Hidden AI Prompt Injection in Court Filings

A self-represented litigant in Connecticut, Matthew Elliott, was sanctioned after embedding hidden prompt-injection text in two court filings in his case against the New York Bariatric Group. The concealed instructions, reportedly placed in tiny white font, told any AI system reviewing the documents to favor his position and were uncovered after court staff noticed unusual white-space patterns in the filings.

Judge Walter Michael Spader Jr. found the tactic was an improper attempt to mislead the court and other parties, even though the Connecticut Judicial Branch said it does not use AI systems to review filings. The court issued a show-cause order and ultimately barred Elliott from filing electronically, requiring future submissions to be made in person on paper, while stopping short of imposing additional sanctions and allowing the underlying case to continue.