diff --git a/requirements-dev.txt b/requirements-dev.txt
index c32dc28..d79737b 100644
--- a/requirements-dev.txt
+++ b/requirements-dev.txt
@@ -7,3 +7,4 @@ pytest>=2.7.0
 sphinx>=1.3.1
 Sphinx-PyPI-upload>=0.2.1
 tox>=1.9.2
+pygments>=2.7.4 # not directly required, pinned by Snyk to avoid a vulnerability