diff --git a/plugins/out_gelf/gelf.c b/plugins/out_gelf/gelf.c
index 0499cddc157..1d18ba0305d 100644
--- a/plugins/out_gelf/gelf.c
+++ b/plugins/out_gelf/gelf.c
@@ -312,6 +312,7 @@ static void cb_gelf_flush(struct flb_event_chunk *event_chunk,
         off = log_decoder.offset;
         size = off - prev_off;
         prev_off = off;
+        s = NULL;
 
         map = *log_event.body;