diff --git a/requirements.txt b/requirements.txt
index 754094d..756eae0 100644
--- a/requirements.txt
+++ b/requirements.txt
@@ -14,3 +14,4 @@ sympy==1.6
 tox==3.25.0
 web3>=5.0.0,<6.0.0
 importlib-metadata>=1.6.1
+urllib3>=1.26.19 # not directly required, pinned by Snyk to avoid a vulnerability