diff --git a/appengine/standard/mailjet/requirements.txt b/appengine/standard/mailjet/requirements.txt
index ca6ba1e7509..76397beb6e5 100644
--- a/appengine/standard/mailjet/requirements.txt
+++ b/appengine/standard/mailjet/requirements.txt
@@ -2,3 +2,4 @@ Flask==1.0.2
 requests==2.21.0
 requests-toolbelt==0.9.1
 mailjet-rest==1.3.0
+urllib3>=2.6.0 # not directly required, pinned by Snyk to avoid a vulnerability