diff --git a/requirements.txt b/requirements.txt
index 9b29db0..1fd2a25 100644
--- a/requirements.txt
+++ b/requirements.txt
@@ -97,7 +97,7 @@ navigator-updater==0.2.1
 nbconvert==5.4.0
 nbformat==4.4.0
 networkx==2.2
-nltk==3.4
+nltk==3.4.5
 nose==1.3.7
 notebook==5.7.4
 numba==0.41.0