diff --git a/3.10-rc/buster/slim/Dockerfile b/3.10-rc/buster/slim/Dockerfile
index 955001e79..bf7feff48 100644
--- a/3.10-rc/buster/slim/Dockerfile
+++ b/3.10-rc/buster/slim/Dockerfile
@@ -4,7 +4,7 @@
 # PLEASE DO NOT EDIT IT DIRECTLY.
 #
 
-FROM debian:buster-slim
+FROM debian:10.12-slim
 
 # ensure local python is preferred over distribution python
 ENV PATH /usr/local/bin:$PATH