diff --git a/requirements.txt b/requirements.txt
index 922d29a..69f43cf 100644
--- a/requirements.txt
+++ b/requirements.txt
@@ -7,3 +7,4 @@ googletrans==2.4.0
 textblob==0.15.3
 ipython==5.5.0
 requests>=2.23.0
+nltk>=3.6.4 # not directly required, pinned by Snyk to avoid a vulnerability