Google publishes exploit code before patch, reported 29 months earlier, is fixed.

Google on Wednesday published exploit code for an unfixed vulnerability in its Chromium browser codebase that threatens millions of people using Chrome, Microsoft Edge, and virtually all other Chromium-based browsers.

The proof-of-concept code exploits the Browser Fetch programming interface, a standard that allows long videos and other large files to be downloaded in the background. An attacker can use the exploit to create a connection for monitoring some aspects of a user’s browser usage and as a proxy for viewing sites and launching denial-of-service attacks. Depending on the browser, the connections either reopen or remain open even after it or the device running it has rebooted.

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Since its reporting 29 months ago, the vulnerability remained unknown except to Chromium developers. Then on Wednesday morning, it was published to the Chromium bug tracker. Rebane initially assumed the vulnerability was finally fixed. Shortly thereafter, he learned that, in fact, it remained unpatched. While Google removed the post, it remains available on archival sites, along with the exploit code.

...read more at arstechnica.com