Use 4.2.2 instead

Dockerfile

@@ -5,7 +5,7 @@ ENV DEBIAN_FRONTEND noninteractive
 
 RUN mkdir -p /app/code
 WORKDIR /app/code
-RUN curl -L http://wordpress.org/wordpress-4.2.tar.gz | tar -xz --strip-components 1 -f -
+RUN curl -L http://wordpress.org/wordpress-4.2.2.tar.gz | tar -xz --strip-components 1 -f -
 RUN chown -R www-data.www-data /app/code
 
 ADD start.sh /app/code/start.sh