diff --git a/Dockerfile b/Dockerfile
index c47b3e7..199da7a 100644
--- a/Dockerfile
+++ b/Dockerfile
@@ -1,4 +1,4 @@
-FROM alpine
+FROM alpine:3.12
 
 RUN apk add --no-cache \
     ca-certificates \
@@ -23,7 +23,7 @@ RUN apk add --no-cache \
     nagios-plugins-tcp \
     nagios-web \
     nrpe-plugin \
-    openssh-client-common \
+    openssh-client \
     openssl \
     perl \
     python3 \
diff --git a/Dockerfile.fcgi b/Dockerfile.fcgi
index 6f64903..fa94f5e 100644
--- a/Dockerfile.fcgi
+++ b/Dockerfile.fcgi
@@ -1,6 +1,6 @@
-FROM alpine
+FROM alpine:3.12
 
-RUN adduser -S -s /sbin/nologin -h /var/www/localhost/htdocs -u 80 -G www-data www-data && \
+RUN adduser -S -s /sbin/nologin -h /var/www/localhost/htdocs -u 80 www-data && \
     apk add --no-cache \
       fcgiwrap \
       nagios \