diff --git a/ci/docker/doc/Dockerfile b/ci/docker/doc/Dockerfile
index 60a0d7c..43932ea 100644
--- a/ci/docker/doc/Dockerfile
+++ b/ci/docker/doc/Dockerfile
@@ -1,7 +1,7 @@
 FROM debian:stable
 
 # for basic Forgejo + AsciiDoctor support
-RUN apt update && apt install -y --no-install-recommends nodejs git ruby-rubygems make && apt clean
+RUN apt update && apt install -y --no-install-recommends nodejs git ruby-rubygems make ca-certificates && apt clean
 
 RUN gem install asciidoctor asciidoctor-diagram
 
diff --git a/ci/docker/impl/Dockerfile b/ci/docker/impl/Dockerfile
index 26227fe..74016da 100644
--- a/ci/docker/impl/Dockerfile
+++ b/ci/docker/impl/Dockerfile
@@ -1,7 +1,7 @@
 FROM debian:stable
 
 # for Forgejo Actions
-RUN apt update && apt install -y --no-install-recommends nodejs git && apt clean
+RUN apt update && apt install -y --no-install-recommends nodejs git ca-certificates && apt clean
 
 # Hamnet70 build dependencies
 RUN apt install -y --no-install-recommends cmake make gcc libc-dev libliquid-dev libhackrf-dev libfec-dev libfftw3-dev && apt clean