There are a number of reasons for exploding K-Cups but the product is not defective. Here are the most common reasons and solutions provided by the manufacturer Keurig on how to fix this issue.
1) There is too much air on the K-Cup. The freshly ground beans release carbon dioxide gas that causes the air in the K-Cup. If the air is not released before brewing it may cause a pop and and overflow of pressure which causes the grounds to push through the holes and into your cup.
Solution: The easiest way to release the air is to put the K-cup in the Keurig close the lid then open. This will release the air prior to brewing.
2) A clogged needle. There are two needles in your Keurig brewer. One punctures the top of the K-cup and the other the bottom. From time to time, coffee or tea particles will get stuck in one of the needles causing a clog, then a backup of water can cause the described explosion.
Solution: To clean the needles use a straightened out paperclip. Insert the paperclip into the needles in an attempt to release any stuck debris. Then run a few water only brew cycles to flush it out. You can also clean your brewer using distilled white vinegar.