diff --git a/revealjs/build.py b/revealjs/build.py
index 61c98cb..e79a116 100755
--- a/revealjs/build.py
+++ b/revealjs/build.py
@@ -48,7 +48,7 @@ for idx, file in enumerate(files):
         parts = f.read().split('---\n')
 
     if idx == 0:
-        config = {**config, **yaml.load(parts[0])}
+        config = {**config, **yaml.safe_load(parts[0])}
         parts = parts[1:]
 
     section_content = '<section>'