diff --git a/cmd/oras/root/manifest/index/create.go b/cmd/oras/root/manifest/index/create.go
index 09ff30887..3e5a2754f 100644
--- a/cmd/oras/root/manifest/index/create.go
+++ b/cmd/oras/root/manifest/index/create.go
@@ -142,7 +142,7 @@ func getPlatform(ctx context.Context, target oras.ReadOnlyTarget, manifestBytes
 		return nil, err
 	}
 	// if config size is larger than 4 MiB, discontinue the fetch
-	if manifest.Config.Size >= maxConfigSize {
+	if manifest.Config.Size > maxConfigSize {
 		return nil, fmt.Errorf("config size %v exceeds MaxBytes %v: %w", manifest.Config.Size, maxConfigSize, errdef.ErrSizeExceedsLimit)
 	}
 	// fetch config content