diff --git a/tieba-cloud-sign/Dockerfile b/tieba-cloud-sign/Dockerfile
index 2eebe6d6..6966b8cd 100644
--- a/tieba-cloud-sign/Dockerfile
+++ b/tieba-cloud-sign/Dockerfile
@@ -1,4 +1,4 @@
-FROM alpine:latest
+FROM alpine:3.18.3
 ENV LANG=zh_CN.UTF-8 \
     TZ=Asia/Shanghai \
     WORKDIR=/var/www \