diff --git a/xkb/xkb.c b/xkb/xkb.c
index c389448e4..b5d601dcb 100644
--- a/xkb/xkb.c
+++ b/xkb/xkb.c
@@ -1647,7 +1647,7 @@ CheckKeyTypes(ClientPtr client,
         }
         n = i + req->firstType;
         width = wire->numLevels;
-        if (width < 1) {
+        if (width < 1 || width > XkbMaxShiftLevel) {
             *nMapsRtrn = _XkbErrCode3(0x04, n, width);
             return 0;
         }