diff --git a/requirements.txt b/requirements.txt
index 43dc3f23..85978b63 100644
--- a/requirements.txt
+++ b/requirements.txt
@@ -13,3 +13,4 @@ scipy
 sphinx
 sphinxcontrib.napoleon
 sphinx_rtd_theme
+urllib3>=2.5.0 # not directly required, pinned by Snyk to avoid a vulnerability