diff --git a/requirements.txt b/requirements.txt
index 155e5c67669..56b969731b6 100644
--- a/requirements.txt
+++ b/requirements.txt
@@ -66,3 +66,4 @@ Unidecode>=1.3.4
 weasyprint>=52.5,<53    # Datatracker tests past on 54, but xml2rfc tests do not.
 xml2rfc>=3.12.4
 xym>=0.6,<1.0
+urllib3>=2.6.3 # not directly required, pinned by Snyk to avoid a vulnerability