BragJack Attack Compromises Major Browser AI Assistants

• •BragJack exploits AI assistants in five major browsers.
• •The attack allows unauthorized access to sensitive user data.
• •Two CVEs were issued, and over $20,000 in bug bounties were awarded.

The BragJack attack exploits vulnerabilities in the AI assistants of five major browsers: Google Chrome, Microsoft Edge, Opera Neon, Perplexity Comet, and Claude in Chrome. Researchers from Forever Security discovered that these vulnerabilities allow attackers to access sensitive data, control local files, and exfiltrate information through malicious browser extensions. The attack does not rely on traditional methods like prompt injection but instead leverages a critical design flaw in how browsers interact with extensions. This flaw allows untrusted extensions to hijack the communication channel with the browser's AI, leading to unauthorized actions. The research resulted in over $20,000 in bug bounties and the issuance of two CVEs: CVE-2026-0628 and CVE-2026-55945. All affected browsers have since patched the vulnerabilities. The attack poses a risk to millions of users globally who utilize these browsers with extensions installed.