diff --git a/Dockerfile b/Dockerfile
index 1052731..4299f43 100644
--- a/Dockerfile
+++ b/Dockerfile
@@ -1,4 +1,4 @@
-FROM debian:bullseye-slim AS snapcast_build
+FROM debian:bullseye-slim@sha256:8eaee63a5ea83744e62d5bf88e7d472d7f19b5feda3bfc6a2304cc074f269269 AS snapcast_build
 
 # renovate: datasource=github-tags depName=badaix/snapcast versioning=semver
 ENV SNAPCAST_VERSION v0.26.0