diff --git a/manual-testing-sandbox/requirements.txt b/manual-testing-sandbox/requirements.txt
index 787755f1d4b..c0b927a8d68 100644
--- a/manual-testing-sandbox/requirements.txt
+++ b/manual-testing-sandbox/requirements.txt
@@ -21,7 +21,7 @@ seaborn==0.11.2
 plotly==5.3.1
 
 # Natural Language Processing
-nltk==3.6.3
+nltk==3.10.3
 spacy==3.1.2
 
 # Deep Learning
@@ -54,4 +54,5 @@ aiohttp==3.7.4
 # Others
 jupyter==1.0.0
 gunicorn==20.1.0
-psycopg2==2.9.1
\ No newline at end of file
+psycopg2==2.9.1
+mistune>=3.3.3 # not directly required, pinned by Snyk to avoid a vulnerability
\ No newline at end of file