{
 "license": "CC-BY-4.0",
 "attribution": "Fide AI, Agentic Cyber Explorer",
 "url": "https://agentic-cyber-explorer.pages.dev/findings/agentic-browsers-act-on-hidden-content/",
 "asOf": "2026-09-26",
 "id": "agentic-browsers-act-on-hidden-content",
 "claim": "Agentic browsers act on page content that users cannot see.",
 "evidenceKind": "measured",
 "scope": "Demonstrations by one research team (Brave, itself a browser maker) across three other browsers; vendors' fixes vary, and one of the cases used visible rather than hidden text.",
 "topics": [
  "prompt-injection"
 ],
 "atlas": [
  "untrusted-content"
 ],
 "evidence": [
  {
   "event": "brave-perplexity-comet-indirect-prompt-injection-2025",
   "note": "Comet acted on instructions hidden in page content (for example white text or a spoiler tag)."
  },
  {
   "event": "brave-unseeable-injections-comet-fellou-2025",
   "note": "Comet read faint text hidden in screenshots; in Fellou the injected page text was visible, but was sent to the model on simple navigation."
  },
  {
   "event": "brave-opera-neon-prompt-injection-2025",
   "note": "Opera Neon's assistant followed instructions in an invisible (opacity 0) page element."
  }
 ],
 "relations": [],
 "statusHistory": [
  {
   "status": "reported",
   "on": "2025-08-20",
   "why": "Brave shows Comet treating page content as instructions.",
   "event": "brave-perplexity-comet-indirect-prompt-injection-2025",
   "kind": "evidence"
  }
 ],
 "halfLifeDays": 365,
 "wouldChange": "Independent replication across browsers, or a browser that separates visible from hidden content.",
 "fideQuestions": [],
 "methods": [
  "indirect-prompt-injection"
 ],
 "review": "assistant-drafted",
 "addedOn": "2026-09-25"
}