Jamieson, Fausset and Brown on Ezekiel 13:4

4. foxes--which cunningly "spoil the vines" (So 2:15), Israel being the vineyard (Psa 80:8-15; Is 5:1-7; 27:2; Jr 2:21); their duty was to have guarded it from being spoiled, whereas they themselves spoiled it by corruptions.

in ... deserts--where there is nothing to eat; whence the foxes become so ravenous and crafty in their devices to get food. So the prophets wander in Israel, a moral desert, unrestrained, greedy of gain which they get by craft.