diff --git a/.woodpecker/build.yml b/.woodpecker/build.yml
index b85b01a..0296942 100644
--- a/.woodpecker/build.yml
+++ b/.woodpecker/build.yml
@@ -3,7 +3,7 @@ depends_on:
   - lint
 steps:
   docker_build_and_push_selfhosted:
-    image: thegeeklab/drone-docker-buildx:23
+    image: thegeeklab/drone-docker-buildx:23@sha256:2c5226dfba416af189fa7ad18cb6fa307a483a08785c9bdbf172e590c450e5d7
     privileged: true
     settings:
       dockerfile: Dockerfile
@@ -23,7 +23,7 @@ steps:
           - tag
 
   docker_build_and_push_selfhosted_tag:
-    image: thegeeklab/drone-docker-buildx:23
+    image: thegeeklab/drone-docker-buildx:23@sha256:2c5226dfba416af189fa7ad18cb6fa307a483a08785c9bdbf172e590c450e5d7
     privileged: true
     settings:
       dockerfile: Dockerfile
diff --git a/.woodpecker/lint.yml b/.woodpecker/lint.yml
index 5ccac95..463384e 100644
--- a/.woodpecker/lint.yml
+++ b/.woodpecker/lint.yml
@@ -1,7 +1,7 @@
 ---
 steps:
   gitleaks:
-    image: zricethezav/gitleaks:v8.18.0
+    image: zricethezav/gitleaks:v8.18.0@sha256:e5f6d1a62786affd1abd882ecc73e9353ce78adea1650711f6e351767723712d
     commands:
       - gitleaks detect --no-git --verbose --source $CI_WORKSPACE
     when:
@@ -9,7 +9,7 @@ steps:
         exclude:
           - tag
   hadolint:
-    image: pipelinecomponents/hadolint:0.25.9
+    image: pipelinecomponents/hadolint:0.25.9@sha256:430e949e6554d56ffc2dd08898ee609c71822d7fa1033f7c4dc240e90f2aac23
     commands:
       - hadolint Dockerfile
     when:
diff --git a/Dockerfile b/Dockerfile
index a8fa89d..85ee890 100644
--- a/Dockerfile
+++ b/Dockerfile
@@ -1,4 +1,4 @@
-FROM alpine:3 AS builder
+FROM alpine:3@sha256:51b67269f354137895d43f3b3d810bfacd3945438e94dc5ac55fdac340352f48 AS builder
 ARG MDNS_REPEATER_VERSION=local
 WORKDIR /
 COPY mdns-repeater.c mdns-repeater.c
@@ -7,7 +7,7 @@ RUN set -ex && \
     apk add --no-cache build-base && \
     gcc -o /bin/mdns-repeater mdns-repeater.c -DMDNS_REPEATER_VERSION=\"${MDNS_REPEATER_VERSION}\"
 
-FROM alpine:3
+FROM alpine:3@sha256:51b67269f354137895d43f3b3d810bfacd3945438e94dc5ac55fdac340352f48
 # hadolint ignore=DL3018
 RUN set -ex && \
     apk add --no-cache vlan libcap bash