Microsoft Severs a Toxic Legacy: IE Mode Deactivated Over Security Threats

It seems like a relic from another time: Internet Explorer Mode, an inconspicuous switch in Microsoft Edge that allows old websites to live on. But this compatibility mode has now proven to be a security hole – and Microsoft is pulling the emergency brake.

An unexpected step backwards in the modern browser

When the Edge team received indications of targeted attacks in August 2025, the findings were clear. Attackers used IE mode to deceive users about fake pages and inject malicious code using an unpatched hole in the old Chakra JavaScript engine. A second vulnerability made it possible to gain higher rights from the browser – full system access was possible. This made it clear: the legacy of Internet Explorer in the new Edge browser was not only decrepit, but acutely dangerous. Internet Explorer mode exists because many companies, authorities and infrastructure systems still use applications that rely on outdated web technologies such as ActiveX, Flash or VBScript. They have often been linked to internal processes for years – such as access controls, management systems or special interfaces.

A complete reconstruction of these structures requires not only technical adjustments, but also new certifications, budgets and training. Even after Internet Explorer was officially shut down in June 2022, a transition mode remained necessary in order to be able to continue to operate these legacy systems without having to switch them off immediately. Microsoft is now reacting decisively: The developers have removed all quick entry points into IE mode – toolbar, context menu, main menu. It can still be activated for companies with central guidelines, but private users must consciously approve each compatibility case via the settings and a page list. This is to prevent social engineering tricks from luring users into the old engine.

IE death is getting closer again

The company also reminds you that the official end of Internet Explorer 11 was on June 15, 2022. The message is clear: Anyone who still uses old web technologies today is exposing their system to unnecessary risk. Modern Chromium browsers not only offer more speed, but also significantly deeper layers of defense. In the long term, this step is likely to further accelerate the slow departure of Internet Explorer. What was intended as a bridge for legacy systems is now increasingly becoming a source of danger – and Microsoft is therefore removing the bridge bit by bit.