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Researchers show one extension could hijack AI assistants in five Chromium products
Forever Security researcher Gal Weizman showed that a single malicious browser extension could take over the AI assistants in Chrome, Perplexity Comet, Microsoft Edge, Opera Neon and the Claude in Chrome extension. The technique, named BragJack, requires the extension to be installed first, and no real-world attacks are known.
Weizman published the findings on Sept. 16. As The Hacker News describes it, browser AI assistants pair a local component, which can view the screen and act in the browser, with a model on the vendor's servers, and the local part takes commands only from a trusted vendor web page. Using two common extension capabilities, injecting scripts into pages and altering network traffic through the declarativeNetRequest interface, the extension placed its own code in that trusted page and issued instructions as if it were the vendor.
Results varied by product, the outlet reported. In Edge, Opera Neon, Comet and Claude in Chrome, the extension could direct the AI agent. In Chrome and Comet it could read local files, and in Chrome it could also switch on the camera and microphone.
Google fixed the Chrome flaw, CVE-2026-0628, in January, and Microsoft patched the Edge issue, CVE-2026-55945, on July 2. The other three findings have no CVE identifiers and rest on the company's own account, the outlet noted. Forever Security says the work earned about $20,000 in bug bounties.
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