diff --git a/Dockerfile.python-deb b/Dockerfile.python-deb
index 3895d67..07e3db7 100644
--- a/Dockerfile.python-deb
+++ b/Dockerfile.python-deb
@@ -9,3 +9,5 @@ COPY apt/99ca /etc/apt/apt.conf.d/99ca
 COPY apt/debian.sources /etc/apt/sources.list.d/debian.sources
 
 COPY python/pip.conf /etc/pip.conf
+
+RUN update-ca-certificates