diff --git a/src/formats/internal/memreader.c b/src/formats/internal/memreader.c
index 5ea3bd88b..b432ec92f 100644
--- a/src/formats/internal/memreader.c
+++ b/src/formats/internal/memreader.c
@@ -49,7 +49,7 @@ void memreader_close(memreader *reader) {
 }
 
 int memread_buf(memreader *reader, char *buf, int len) {
-    if(reader->pos + len > reader->len) {
+    if(reader->pos + len > reader->len || buf == NULL || reader->buf == NULL) {
         return 0;
     }
     memcpy(buf, reader->buf + reader->pos, len);