SpecterDev has released his WebKit exploit, this is NOT a kernel exploit. If you have 6.20 and under it should run okay, there was an update over the past couple of days from PSN which stops the exploit working.
Read more here: https://mobile.twitter.com/SpecterDev/status/1104085876831735808
Read more here: https://mobile.twitter.com/SpecterDev/status/1104085876831735808