diff --git a/src/isomedia/isom_read.c b/src/isomedia/isom_read.c
index d140b1b0b1..f978ca32f2 100644
--- a/src/isomedia/isom_read.c
+++ b/src/isomedia/isom_read.c
@@ -2721,6 +2721,11 @@ GF_Err gf_isom_get_user_data(GF_ISOFile *movie, u32 trackNumber, u32 UserDataTyp
 		ptr = (GF_UnknownBox*)gf_list_get(map->boxes, UserDataIndex-1);
 
 		if (ptr->type == GF_ISOM_BOX_TYPE_UNKNOWN) {
+			if (!ptr->dataSize) {
+				*userData = NULL;
+				*userDataSize = 0;
+				return GF_OK;
+			}
 			*userData = (char *)gf_malloc(sizeof(char)*ptr->dataSize);
 			if (!*userData) return GF_OUT_OF_MEM;
 			memcpy(*userData, ptr->data, sizeof(char)*ptr->dataSize);
@@ -2728,6 +2733,11 @@ GF_Err gf_isom_get_user_data(GF_ISOFile *movie, u32 trackNumber, u32 UserDataTyp
 			return GF_OK;
 		} else if (ptr->type == GF_ISOM_BOX_TYPE_UUID) {
 			GF_UnknownUUIDBox *p_uuid = (GF_UnknownUUIDBox *)ptr;
+			if (!p_uuid->dataSize) {
+				*userData = NULL;
+				*userDataSize = 0;
+				return GF_OK;
+			}
 			*userData = (char *)gf_malloc(sizeof(char)*p_uuid->dataSize);
 			if (!*userData) return GF_OUT_OF_MEM;
 			memcpy(*userData, p_uuid->data, sizeof(char)*p_uuid->dataSize);