diff --git a/requirements.txt b/requirements.txt
index e87080e..7adc17c 100644
--- a/requirements.txt
+++ b/requirements.txt
@@ -17,3 +17,6 @@ accessstatsapi==1.2.0
 publicationstatsapi==1.2.0
 articlemetaapi==1.14.19
 altmetric==1.0.0
+certifi>=2023.7.22 # not directly required, pinned by Snyk to avoid a vulnerability
+mako>=1.2.2 # not directly required, pinned by Snyk to avoid a vulnerability
+pygments>=2.15.0 # not directly required, pinned by Snyk to avoid a vulnerability