Paper/nms-patches/EntityFireworks.patch

--- a/net/minecraft/server/EntityFireworks.java
+++ b/net/minecraft/server/EntityFireworks.java
@@ -79,7 +79,7 @@
         }
 
         if (!this.world.isClientSide && this.ticksFlown > this.expectedLifespan) {
-            this.world.broadcastEntityEffect(this, (byte) 17);
+            if (!org.bukkit.craftbukkit.event.CraftEventFactory.callFireworkExplodeEvent(this).isCancelled()) this.world.broadcastEntityEffect(this, (byte) 17); // CraftBukkit
             this.die();
         }