diff --git a/requirements_dev.txt b/requirements_dev.txt
index 486da6e..8207f84 100644
--- a/requirements_dev.txt
+++ b/requirements_dev.txt
@@ -10,3 +10,4 @@ twine==1.11.0
 
 pytest==3.5.0
 pytest-runner==4.2
+pygments>=2.7.4 # not directly required, pinned by Snyk to avoid a vulnerability