diff --git a/src/runtime.c b/src/runtime.c
index a3659348..ab46db1a 100644
--- a/src/runtime.c
+++ b/src/runtime.c
@@ -1013,6 +1013,7 @@ hs_error_t HS_CDECL hs_close_stream(hs_stream_t *id, hs_scratch_t *scratch,
         report_eod_matches(id, scratch, onEvent, context);
         if (unlikely(internal_matching_error(scratch))) {
             unmarkScratchInUse(scratch);
+            hs_stream_free(id);
             return HS_UNKNOWN_ERROR;
         }
         unmarkScratchInUse(scratch);