diff --git a/docker-compose.sample.yml b/docker-compose.sample.yml
index 64e090a..cdf85a0 100644
--- a/docker-compose.sample.yml
+++ b/docker-compose.sample.yml
@@ -14,7 +14,7 @@
       - phpsessions:/var/phpsessions
     restart: unless-stopped
   db:
-    image: mariadb
+    image: mariadb@sha256:9da6213d1a5714c4585c9c0003c51510b320d6f60e53d78701fe1e194126249f
     environment:
       MYSQL_ALLOW_EMPTY_PASSWORD: "yes"
       MARIADB_DATABASE: ${DB_NAME}