diff --git a/contrib/build_tools_util.sh b/contrib/build_tools_util.sh
index 94d2cdbe9..9cba7cb4f 100755
--- a/contrib/build_tools_util.sh
+++ b/contrib/build_tools_util.sh
@@ -1,5 +1,8 @@
 #!/usr/bin/env bash
 
+# Set a fixed umask as this leaks into docker containers
+umask 0022
+
 RED='\033[0;31m'
 BLUE='\033[0;34m'
 YELLOW='\033[0;33m'