The BragJack attack exploits a novel technique called DiNneR Serving, which abuses the declarativeNetRequest API permissions in Chromium-based browsers to weaken security headers like Content-Security-Policy and redirect JavaScript resources to malicious payloads. This enables a malicious extension to inject code into privileged internal browser agents or embedded web views, such as Chrome's Gemini Live agent (chrome://glic embedding gemini.google.com). By removing or modifying security headers and redirecting script resources, the attack bypasses protections that normally prevent extensions from interacting with these privileged contexts. The impact includes unauthorized access to local files, browsing history, camera and microphone, screenshots, and browser profile data, often without requiring user interaction. The attack was demonstrated successfully against Chrome, Comet, Edge, Opera Neon, and Claude in Chrome, yielding two CVEs (CVE-2026-0628 and CVE-2026-55945) and significant bounty rewards. The attack uses a standard manifest.json extension with DNR rules customized per target browser. The research highlights a systemic issue in how Chromium-based browsers handle DNR permissions and embedded web views.

The attack allows malicious extensions to execute arbitrary code within privileged browser contexts, leading to unauthorized access to sensitive data and capabilities including local file access, browsing history, camera and microphone, screenshots, and browser profile leaks. The attack can be performed without user interaction (zero-click). This compromises user privacy and security across multiple popular Chromium-based browsers. The impact varies by browser but includes high-risk capabilities such as local file system access and media device control.

Patch status is not yet confirmed — check the vendor advisories for current remediation guidance. Since the attack exploits the declarativeNetRequest API and browser security header enforcement, vendors need to update their browsers to restrict or properly enforce DNR permissions within privileged contexts and embedded web views. Users should monitor vendor advisories for updates and remove untrusted extensions. No vendor advisory or official fix information was provided in the source data.