{
 "public_id": "AIR-2026-0141",
 "incident_id": "2026-06-anthropic-computer-use-toctou",
 "date_disclosed": "2026-06-25",
 "date_occurred": null,
 "title": "Computer-use TOCTOU: swapping UI elements during inference so the agent clicks something else",
 "class": "research_demo",
 "attack_surface": "computer_use_agent",
 "initial_vector": "malicious_web_ui",
 "agent_capability_abused": [
  "screenshot_perception",
  "gui_clicking"
 ],
 "target_product": "Claude Computer Use",
 "target_vendor": "Anthropic",
 "autonomy_level": "semi_autonomous",
 "impact_realized": false,
 "impact_type": [
  "unauthorized_action",
  "data_exfiltration"
 ],
 "blast_radius": "computer-use agents that act on stale screenshots",
 "cve": [],
 "taxonomy": {
  "owasp_asi": [
   "ASI04",
   "ASI02"
  ],
  "mitre_atlas": [],
  "labels": [
   "toctou",
   "race_condition",
   "ui_redress",
   "computer_use"
  ]
 },
 "defense_present": null,
 "defense_bypassed": null,
 "fix_shipped": "Anthropic added pixel-change verification before taking actions (per its Cowork announcement)",
 "primary_sources": [
  "https://embracethered.com/blog/posts/2026/toctou-agent-what-you-click-is-not-what-you-get/"
 ],
 "verified_quote": "The Agent will think it clicks the Continue button, but in reality it clicks \"Send\" to send an arbitrary email.",
 "confidence": "high",
 "notes": "Johann Rehberger. Class of bug applies to any screenshot-then-act computer-use loop, not only Anthropic's.",
 "risk_category": "security_fraud",
 "risk_secondary": [
  "privacy"
 ],
 "risk_subcategory": "Unclassified",
 "risk_sub_secondary": [],
 "ai_entity": "generative",
 "agency": "agent_acted",
 "agency_debatable": false,
 "agency_reason": "the agent clicked the swapped UI element and sent the email",
 "vector_family": "malicious_component",
 "vector_detail": "malicious_web_ui",
 "guardrail_kind": [
  "unknown"
 ],
 "guardrail_outcome": "silent",
 "xrefs": {
  "aiid": [],
  "atlas": [],
  "cve": [],
  "ghsa": []
 },
 "primary_asi": "ASI04",
 "agent_framework": "claude_computer_use",
 "model_provider": "anthropic",
 "model_name": "",
 "detection_mechanism": "external_researcher",
 "tool_access": "unknown",
 "financial_loss_band": "unknown",
 "eai_category": "unsafe_actuation",
 "eai_domain": "agent_behaviour",
 "eai_secondary": [
  "data_exfiltration_channels"
 ],
 "eai_reason": "impact rule: unsafe_actuation",
 "asi_curated": [],
 "asi_scope": "in_scope",
 "asi_provenance": "rule",
 "asi_reason": "ASI04 (vector_family=malicious_component); ASI02 (impact=tool_misuse)",
 "submitted_by": "EAI Internal"
}