diff --git a/requirements.txt b/requirements.txt
index 72e6b42..e646f24 100644
--- a/requirements.txt
+++ b/requirements.txt
@@ -2,3 +2,4 @@ requests>=2.22.0
 matplotlib>=3.1.2
 geographiclib>=1.50
 overpy>=0.4
+pillow>=10.0.0 # not directly required, pinned by Snyk to avoid a vulnerability