diff --git a/libavfilter/vf_dnn_detect.c b/libavfilter/vf_dnn_detect.c
index 5668b8b017..3464af86c8 100644
--- a/libavfilter/vf_dnn_detect.c
+++ b/libavfilter/vf_dnn_detect.c
@@ -223,6 +223,7 @@ static int dnn_detect_parse_yolo_output(AVFrame *frame, DNNData *output, int out
                     av_freep(&bbox);
                     return AVERROR(ENOMEM);
                 }
+                bbox = NULL;
             }
     }
     return 0;