diff --git a/tools/zircolite_server/requirements.txt b/tools/zircolite_server/requirements.txt
index fb52653..14829bb 100644
--- a/tools/zircolite_server/requirements.txt
+++ b/tools/zircolite_server/requirements.txt
@@ -1,2 +1,3 @@
 flask>=1.1.2
 jinja2>=2.11.3
+werkzeug>=2.3.8 # not directly required, pinned by Snyk to avoid a vulnerability