diff --git a/libsparse/output_file.cpp b/libsparse/output_file.cpp
index c5c4960..e35cb0d 100644
--- a/libsparse/output_file.cpp
+++ b/libsparse/output_file.cpp
@@ -493,6 +493,10 @@
 
 void output_file_close(struct output_file* out) {
   out->sparse_ops->write_end_chunk(out);
+  free(out->zero_buf);
+  free(out->fill_buf);
+  out->zero_buf = nullptr;
+  out->fill_buf = nullptr;
   out->ops->close(out);
 }