GHSA-MJGF-XJ26-9QF9 pay-rails/pay: non-constant-time HMAC comparison in Paddle Billing webhook signature verifier

Summary Pay::Webhooks::PaddleBillingControllervalidsignature? app/controllers/pay/webhooks/paddlebillingcontroller.rb verifies the Paddle Billing webhook signature by computing OpenSSL::HMAC.hexdigest... and comparing it to the attacker-supplied header value using Ruby's String==. Ruby's == is...