Security Researchers Expose BragJack Attack: Malicious Extensions Can Hijack AI Agents in Five Major Browsers

Security researchers have uncovered a critical vulnerability technique called BragJack that allows malicious browser extensions to seize control of AI assistants in Chrome, Microsoft Edge, Opera Neon, Perplexity Comet, and Claude in Chrome. The attack exploits fundamental architectural flaws in how browser-based AI agents communicate with their backend systems, enabling attackers to force AI models to execute arbitrary commands without any model-level safety guardrails.