Polyfill Supply Chain Attack: What It Is and How to Know If You’re Affected

Here’s what you need to know about the progression of the Polyfill supply chain attack and how to respond. 
Overview of Polyfill Supply Chain Attack 
On June 25th, 2024, researchers at Sansec disclosed a supply chain attack affecting the polyfill.io content delivery network domain. This domain distributes the open-source polyfill.js library, which increases the compatible feature set of older browsers. In February 2024, the Chinese company Funnull acquired the polyfill.io domain. Sometime after that, the polyfill.io CDN began distributing malicious …

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