Temporal UI State Inconsistency in Desktop GUI Agents: Formalizing and Defending against TOCTOU Attacks on Computer-Use Agents

GUI agents that control desktop computers via screenshot-and-click loops introduce a new class of vulnerability: the observation-to-action gap mean 6.51 s on real OSWorld workloads creates a Time-Of-Check, Time-Of-Use TOCTOU window during which an unprivileged attacker can manipulate the UI state...