This is physical damage (not a disease) and is fortunately not concerning. The tender skin of young cucumber fruits is easily injured, and some (or all) of the scarring could have been caused by the vines themselves (and their prickles), by fencing or trellising if you've trained the plants up a support, or by mulch rubbing against the fruits as they lay on the ground. If you are also seeing foliage feeding damage, it's possible that Cucumber Beetles or some other insect chewed into the skin of the fruit, causing the scarring damage, though the individual fruit pictured doesn't appear to be damaged by insects.

Miri