BragJack Hijacks AI Browser Agents via Malicious Extensions
Security researcher Gal Weizman has disclosed BragJack, a browser extension-based attack technique capable of hijacking AI assistants embedded in Chromium browsers — including Chrome's Gemini Live, Perplexity Comet, Microsoft Edge, Opera Neon, and Anthropic's Claude. By exploiting Chromium's declarativeNetRequest API to weaken security headers and redirect JavaScript resources, a malicious extension can execute code inside privileged AI contexts without any user interaction. The attack has real-world consequence: compromised AI agents could read local files, exfiltrate data, or act on behalf of victims using existing browser-level privileges.