diff --git a/libavutil/file.c b/libavutil/file.c
index b91c2fa391..f228b723ec 100644
--- a/libavutil/file.c
+++ b/libavutil/file.c
@@ -143,7 +143,7 @@ out:
 
 void av_file_unmap(uint8_t *bufptr, size_t size)
 {
-    if (!size)
+    if (!size || !bufptr)
         return;
 #if HAVE_MMAP
     munmap(bufptr, size);