diff --git a/.ci/setup.sh b/.ci/setup.sh
index 792972fbfc2d..ef84a51cd587 100755
--- a/.ci/setup.sh
+++ b/.ci/setup.sh
@@ -98,9 +98,15 @@ else  # Linux
                 clang \
                 libomp-dev
         fi
-        curl -sL https://apt.kitware.com/keys/kitware-archive-latest.asc | apt-key add -
+        curl \
+            -s \
+            -L \
+            --insecure \
+            https://apt.kitware.com/keys/kitware-archive-latest.asc \
+        | apt-key add -
         apt-add-repository "deb https://apt.kitware.com/ubuntu/ $(lsb_release -cs) main" -y
-        apt-get update
+        apt-get --allow-unauthenticated upgrade -y
+        apt-get --allow-unauthenticated update -y
         apt-get install --no-install-recommends -y \
             cmake
     else