diff --git a/gitlab-ci/Dockerfile b/gitlab-ci/Dockerfile
index 6b586562a6cc41b4140ecc180d31d5a3d7240adc..153275481aa86540e1c309238718312d26d910ee 100644
--- a/gitlab-ci/Dockerfile
+++ b/gitlab-ci/Dockerfile
@@ -12,7 +12,7 @@ ENV PATH="$PATH:$EXTLIB/bin"
 ENV PERL_CPANM_HOME="/cpanm/"
 
 RUN apt-get update; \
-    apt-get install -y --no-install-recommends gnupg wget; \
+    apt-get install -y --no-install-recommends gnupg wget ca-certificates; \
     wget -O - https://sdvdebianrepo.slub-dresden.de/deb-repository/pub.gpg.key | apt-key add - ; \
     echo "deb https://sdvdebianrepo.slub-dresden.de/deb-repository "${DEBIAN_RELEASE}" main" > /etc/apt/sources.list.d/slub.list;