diff --git a/src/decoder.c b/src/decoder.c
index 8e3f4370f..9f4cb4c16 100644
--- a/src/decoder.c
+++ b/src/decoder.c
@@ -171,7 +171,7 @@ sixel_decoder_setopt(
 
     switch(arg) {
     case SIXEL_OPTFLAG_INPUT:  /* i */
-        free(decoder->input);
+        sixel_allocator_free(decoder->allocator, decoder->input);
         decoder->input = strdup_with_allocator(value, decoder->allocator);
         if (decoder->input == NULL) {
             sixel_helper_set_additional_message(
@@ -181,7 +181,7 @@ sixel_decoder_setopt(
         }
         break;
     case SIXEL_OPTFLAG_OUTPUT:  /* o */
-        free(decoder->output);
+        sixel_allocator_free(decoder->allocator, decoder->output);
         decoder->output = strdup_with_allocator(value, decoder->allocator);
         if (decoder->output == NULL) {
             sixel_helper_set_additional_message(
diff --git a/src/fromsixel.c b/src/fromsixel.c
index 198820958..77301cc5e 100644
--- a/src/fromsixel.c
+++ b/src/fromsixel.c
@@ -1076,7 +1076,7 @@ sixel_decode_raw(
     goto end;
 
 error:
-    free(image.data);
+    sixel_allocator_free(allocator, image.data);
     image.data = NULL;
 
 end: