diff --git a/c/aws-c-common/aws_string_eq_byte_buf_harness.i b/c/aws-c-common/aws_string_eq_byte_buf_harness.i
index 2409f1fe18f..87ea7f60285 100644
--- a/c/aws-c-common/aws_string_eq_byte_buf_harness.i
+++ b/c/aws-c-common/aws_string_eq_byte_buf_harness.i
@@ -6860,7 +6860,7 @@ struct aws_string *ensure_string_is_allocated_nondet_length() {
 
 struct aws_string *ensure_string_is_allocated_bounded_length(size_t max_size) {
     size_t len = nondet_uint64_t();
-    assume_abort_if_not(len < max_size);
+    assume_abort_if_not(0 < len && len < max_size);
     return ensure_string_is_allocated(len);
 }
 
diff --git a/c/aws-c-common/aws_string_new_from_array_harness.i b/c/aws-c-common/aws_string_new_from_array_harness.i
index 8e630861f92..20c602b1772 100644
--- a/c/aws-c-common/aws_string_new_from_array_harness.i
+++ b/c/aws-c-common/aws_string_new_from_array_harness.i
@@ -9460,10 +9460,11 @@ struct aws_string *aws_string_clone_or_reuse(struct aws_allocator *allocator, co
 }
 void aws_string_new_from_array_harness() {
 
-    size_t alloc_size;
+    size_t alloc_size = nondet_size_t();
+    assume_abort_if_not(alloc_size > 0);
     uint8_t *array = bounded_malloc(alloc_size);
     struct aws_allocator *allocator = can_fail_allocator();
-    size_t reported_size;
+    size_t reported_size = nondet_size_t();
 
 
     assume_abort_if_not(reported_size <= alloc_size);