Cantaloupe squished out overnight
Picked off my vine a solid full mature canteloupe yesterday, placed it on the kitchen counter and this morning found it sort of exploded into a nasty sloppy mess spewing fruit and seeds all over the counter.
Soft fruit rots are pretty common on cucurbits like muskmelon. It may be something like Rhizopus fruit rot, a soft rot that enters through stem scars. It's extremely important to cool melons as fast as possible after picking to keep these rots at bay. Leaving a melon on the kitchen counter, even overnight, gives these post harvest rots time to do damage internally.
Hope this helps.