diff --git a/libavformat/movenc.c b/libavformat/movenc.c
index 6ed93d89ea..5454a9172c 100644
--- a/libavformat/movenc.c
+++ b/libavformat/movenc.c
@@ -6284,9 +6284,11 @@ static void mov_free(AVFormatContext *s)
             av_freep(&mov->tracks[i].vos_data);
 
         ff_mov_cenc_free(&mov->tracks[i].cenc);
+        ffio_free_dyn_buf(&mov->tracks[i].mdat_buf);
     }
 
     av_freep(&mov->tracks);
+    ffio_free_dyn_buf(&mov->mdat_buf);
 }
 
 static uint32_t rgb_to_yuv(uint32_t rgb)