diff --git a/requirements.txt b/requirements.txt
index 5c1e98e..1cb9f56 100644
--- a/requirements.txt
+++ b/requirements.txt
@@ -3,3 +3,4 @@ redis==2.10.6
 cloudconvert==1.0.0
 itchat==1.3.9
 PyPDF2==1.26.0
+urllib3>=2.5.0 # not directly required, pinned by Snyk to avoid a vulnerability