Google published proof-of-concept exploit code for an unfixed Browser Fetch vulnerability in the Chromium codebase on Wednesday, affecting Chrome, Edge and other Chromium-based browsers. The vulnerability, privately reported by researcher Lyra Rebane in late 2022 and rated S1 severity, enables background download connections for user activity monitoring and limited proxy functions, with persistence across reboots as detailed in the Chromium bug tracker thread. Archival records show the code remained accessible after temporary removal from the public tracker, consistent with prior patterns in Chromium disclosures such as those tracked in CVE-2023-2033 reports on delayed API patches. Cross-referenced sources including the official Chromium Gerrit logs and a 2024 MITRE analysis of browser botnet risks confirm the 29-month unfixed window and potential for scaled device networks.