Eurostar Accused Researchers of Blackmail for Reporting AI Chatbot Flaws

Researchers discovered critical flaws in Eurostar’s AI chatbot including prompt injection, HTML injection, guardrail bypass, and unverified chat IDs – Eurostar later accused them of blackmail.

The rush to add AI to customer service, which we have been witnessing lately in almost every sector, can sometimes come at a high price for security. On December 22, 2025, the team of ethical hackers at Pen Test Partners (PTP) went public with a series of flaws they found in the new AI chatbot for Eurostar.

For your information, Eurostar is the famous high-speed rail operator that connects the UK to mainland Europe through the Channel Tunnel, carrying millions of travellers between major hubs like London, Paris, and Amsterdam.

How The Flaws Were Discovered

What started as a researcher planning a simple train trip from London turned into the discovery of “weak guardrails” that left the system open to manipulation. For your information ...