PlayStation Knowledge Center
This article provides information on Flash support in the PS4 web browser.
The PlayStation 4 web browser does not support the Flash plug-in. This means that some websites that require the Flash plug-in may not display or function as intended. In many cases, visiting the mobile version of a website will yield a more PS4-friendly iteration.
We do not have information on any future plans regarding the inclusion of Flash in the PS4's web browser.