Both Google and Microsoft enforce code review pipelines, but review fatigue and automated loopholes remain a stubborn vulnerability. When an extension is initially submitted, it undergoes automated sandboxing. The original build of these download tools complied strictly with developer guidelines.
The breakdown occurs in how updates are evaluated. While Manifest V3 was intended to curb arbitrary remote code execution by disallowing external JavaScript injection, developers found ways to circumvent restrictions. By embedding dynamic evaluation logic directly into background service workers and using server-side configurations to alter runtime behavior, the extensions weaponized basic permissions.
Microsoft Edge faced parallel exposure. Because Edge shares the Chromium foundation, bad actors easily ported their extensions to the Edge Add-ons catalog. Cross-platform distribution allowed the campaign to double its operational footprint within weeks.
