diff --git a/sys/contrib/libnv/nvlist.c b/sys/contrib/libnv/nvlist.c
index 1dc0bb8c114..00ba3b41f3a 100644
--- a/sys/contrib/libnv/nvlist.c
+++ b/sys/contrib/libnv/nvlist.c
@@ -1022,7 +1022,7 @@ static bool
 nvlist_check_header(struct nvlist_header *nvlhdrp)
 {
 
-	if (nvlhdrp->nvlh_size > SIZE_MAX - sizeof(nvlhdrp)) {
+	if (nvlhdrp->nvlh_size > SIZE_MAX - sizeof(*nvlhdrp)) {
 		ERRNO_SET(EINVAL);
 		return (false);
 	}