Google publishes exploit code threatening millions of Chromium users

A reported Chromium vulnerability allows attackers to misuse the Background Fetch/service worker APIs so a malicious site can launch a persistently active service worker and stealthy downloads; the issue affects Chrome and other Chromium-based browsers (Brave, Opera, Vivaldi, Arc), while Firefox and Safari are not vulnerable. The researcher reported long delays in patching, Google acknowledged the code publication and is working on a fix, and developers indicate limited observed use of the background fetch feature with no clear evidence of large-scale exploitation.