diff --git a/core/drupalci.yml b/core/drupalci.yml
index 2c05556125..47947edd03 100644
--- a/core/drupalci.yml
+++ b/core/drupalci.yml
@@ -18,6 +18,7 @@ build:
       # Update PHPUnit & friends.
       container_command:
         commands:
+          - "sudo -u www-data /usr/local/bin/composer self-update --snapshot"
           - "sudo -u www-data /usr/local/bin/composer require composer/composer:dev-master mikey179/vfsstream:dev-master --no-progress"
       # run_tests task is executed several times in order of performance speeds.
       # halt-on-fail can be set on the run_tests tasks in order to fail fast.