diff --git a/ci/docker/Dockerfile.build.ubuntu_cpu_jekyll b/ci/docker/Dockerfile.build.ubuntu_cpu_jekyll
index 62db71e2429e..3dc845dfe69d 100644
--- a/ci/docker/Dockerfile.build.ubuntu_cpu_jekyll
+++ b/ci/docker/Dockerfile.build.ubuntu_cpu_jekyll
@@ -43,7 +43,7 @@ RUN curl -sSL https://rvm.io/mpapis.asc | gpg2 --import - && \
 
 RUN source /etc/profile.d/rvm.sh && \
     rvm requirements && \
-    rvm install 2.6 && \
+    rvm install 2.6.3 && \
     rvm use 2.6.3 --default
 
 ENV BUNDLE_HOME=/work/deps/bundle
@@ -65,4 +65,4 @@ RUN chown -R jenkins_slave /work/ && \
     chown -R jenkins_slave /usr/local/bin && \
     chown -R jenkins_slave /usr/local/rvm
 
-WORKDIR /work/mxnet
\ No newline at end of file
+WORKDIR /work/mxnet