diff --git a/ArcFormats/Edoire/ArcARC.cs b/ArcFormats/Edoire/ArcARC.cs
index f9131806..ce664846 100644
--- a/ArcFormats/Edoire/ArcARC.cs
+++ b/ArcFormats/Edoire/ArcARC.cs
@@ -49,6 +49,8 @@ namespace GameRes.Formats.Edoire
             if (!file.View.AsciiEqual (0, "@ARCH000"))
                 return null;
             var index_offset = file.View.ReadInt64 (file.MaxOffset-8);
+            if (index_offset >= file.MaxOffset-12)
+                return null;
             var count = file.View.ReadInt32 (index_offset);
             if (!IsSaneCount (count))
                 return null;