diff --git a/Dockerfile b/Dockerfile
index 7f3d694..43a3841 100644
--- a/Dockerfile
+++ b/Dockerfile
@@ -1,4 +1,4 @@
-FROM php:8.1-apache
+FROM php:8.1-apache@sha256:e20df709ac9611fde1447de4b56c169520e275d9fca3da0faf9f109e8d0c5b3f
 RUN docker-php-ext-install mysqli
 RUN docker-php-ext-enable mysqli
 RUN mkdir -p /var/phpsessions && chown www-data /var/phpsessions