diff --git a/MetadataExtractor/IO/BufferReader.cs b/MetadataExtractor/IO/BufferReader.cs
index 0c237b67f..d5143003d 100644
--- a/MetadataExtractor/IO/BufferReader.cs
+++ b/MetadataExtractor/IO/BufferReader.cs
@@ -114,8 +114,7 @@ public long GetInt64()
 
     public ulong GetUInt64()
     {
-        var bytes = _bytes.Slice(_position, 8);
-        Advance(8);
+        var bytes = Advance(8);
 
         return _isBigEndian
             ? BinaryPrimitives.ReadUInt64BigEndian(bytes)