diff --git a/requirements.txt b/requirements.txt
index dfef9fec9..1acb55720 100644
--- a/requirements.txt
+++ b/requirements.txt
@@ -58,3 +58,4 @@ toml==0.10.0
 xmltodict==0.10.2
 yamllint==1.15.0
 #pyyaml>=5.4 # not directly required, pinned by Snyk to avoid a vulnerability. update: this breaks Python 3.5 build where this requirement is not found
+pyyaml>=5.3.1 # not directly required, pinned by Snyk to avoid a vulnerability