Russia has put a lot of effort into their hypersonic weapons programs and it was thought that they were well ahead of similar US efforts. Their hypersonic inventory has things like

-Air launched missiles from fighter jets
-Short range ballistic missiles
-Other land- and submarine-launched rockets

What made Putin brag about them was their ability to hit speeds of Mach 5+ while still retaining the ability to maneuver in the atmosphere. One class of their rockets was specifically designed to defeat the American THAAD system (Terminal High Altitude Area Defense).

As the war has ground on Putin's begun using these in the Ukraine. There's a problem, though - we've given the Ukrainians Patriot missiles.

And on a recent raid, the Patriot - a system introduced roughly 30 years ago - went 18 for 18 in shooting down Putin's vaunted wonder weapons. Ooops.

So he's doing what any thug would do - blaming his engineers for leaking secrets:

dailymail.co.uk - Russia detains three hypersonic rocket scientists treason charges despite outcry

Russia detains three hypersonic rocket scientists as Kremlin is left reeling over claims 'dagger' missiles were shot down by Ukraine's Patriot defence system
Dr Valery Zvegintsev, 78, is the latest of three prominent scientists to be arrested
All three face treason charges despite outcry from their scientific colleagues
It comes as Ukraine claimed it shot down several Russian hypersonic missiles