Analysis · curated 10 Sep 2026
What Is Prompt Injection? Real-World Examples and How to Defend Against It
First reported firecrawl.dev
Coverage timeline
Single-source analysis — first reported, latest, and curated coincide.
Why it matters
Prompt injection via hidden text on web pages is a growing vector that can silently bias or hijack AI agents during normal browsing and scraping workflows, so defenders need to understand and mitigate it.
Firecrawl's blog explainer defines prompt injection as instructions hidden inside data that an AI agent ingests and mistakes for commands, illustrating with real examples: a LinkedIn profile prompt making recruiters address the user as 'Lord Arthur' in Old English, hidden arXiv prompts telling agents to leave positive paper reviews, and destructive commands aimed at coding agents. The piece then promotes Firecrawl's defensive features such as checkPromptInjection classification and Lockdown Mode to filter poisoned pages before they reach an agent.