Can my employer limit my 457 contributions?

[Accrorn]

I've attempted to use google to figure this out but I'm obviously putting in the wrong keywords.  My employer is limiting my 457 contributions to 25% of my pay which is lower than the 18000 dollar IRS limit. 

I'm trying to figure out if they can do this and if not, find literature to support my findings.  Hopefully I posted this on the right board.

[BlueHouse]

I know employers can do this with 401ks, so probably the same with 457.