diff --git a/python/requirements.txt b/python/requirements.txt
index c28133c67f6c85e3dd12b08914c7aa0848a4cad7..3dd93093ad3a8f3fd6ff8c3b3e41c8a84ffebd81 100644
--- a/python/requirements.txt
+++ b/python/requirements.txt
@@ -7,7 +7,7 @@ protobuf>=3.12.2
 grpcio-tools>=1.28.1
 grpcio>=1.28.1
 func-timeout>=4.3.5
-pyyaml>=1.3.0
+pyyaml>=1.3.0, <6.0
 flask>=1.1.2
 click==7.1.2
 itsdangerous==1.1.0
diff --git a/python/requirements_mac.txt b/python/requirements_mac.txt
index b14fbd5fc5b779e6f2d216df434bfeb615d59b05..fb289aea74257195b74ce600082f69905eafe774 100644
--- a/python/requirements_mac.txt
+++ b/python/requirements_mac.txt
@@ -6,7 +6,7 @@ google>=2.0.3
 opencv-python==4.2.0.32
 protobuf>=3.12.2
 func-timeout>=4.3.5
-pyyaml>=1.3.0
+pyyaml>=1.3.0, <6.0
 flask>=1.1.2
 click==7.1.2
 itsdangerous==1.1.0