diff --git a/python/requirements-optional.txt b/python/requirements-optional.txt
index 77de05af3..5d2371315 100644
--- a/python/requirements-optional.txt
+++ b/python/requirements-optional.txt
@@ -3,3 +3,5 @@ web3 >= 4.8
 Pillow
 stellar-sdk>=4.0.0,<6.0.0
 rlp>=1.1.0 ; python_version<'3.7'
+protobuf>=4.25.8 # not directly required, pinned by Snyk to avoid a vulnerability
+urllib3>=2.5.0 # not directly required, pinned by Snyk to avoid a vulnerability