diff --git a/docs/requirements.txt b/docs/requirements.txt
index dc6b1803..b804e683 100644
--- a/docs/requirements.txt
+++ b/docs/requirements.txt
@@ -1,3 +1,4 @@
 sphinx
 sphinx_rtd_theme
 pygments-lexer-solidity
+urllib3>=2.2.2 # not directly required, pinned by Snyk to avoid a vulnerability