diff --git a/client/Dockerfile b/client/Dockerfile
index 68a683c..c832d25 100644
--- a/client/Dockerfile
+++ b/client/Dockerfile
@@ -4,5 +4,5 @@
 #
 # As of alpine:3.7, tftp client is in busybox-extras.
 ############################################################
-FROM alpine:3.12.0
+FROM alpine:3.15.4
 RUN apk add --no-cache busybox-extras
diff --git a/src/Dockerfile b/src/Dockerfile
index c911be7..eac069b 100644
--- a/src/Dockerfile
+++ b/src/Dockerfile
@@ -1,4 +1,4 @@
-FROM alpine:3.12.0
+FROM alpine:3.15.4
 
 # Publish the typical syslinux and pxelinux files at tftp root.
 # We only need one subtree of files from syslinux, and