diff --git a/requirements.txt b/requirements.txt
index e1d97d7..2e34ec8 100644
--- a/requirements.txt
+++ b/requirements.txt
@@ -1,5 +1,5 @@
 Jinja2==2.7.2
-MarkupSafe==0.19
+MarkupSafe==0.21
 Pygments==1.6
 Sphinx==1.2.2
 coverage==3.7.1