Dokku is a docker-powered platform as a service. In Dokku versions before 0.38.25, a user with app-level Dokku access and remote SSH access to execute docker-options commands can store arbitrary strings through the docker-options plugin, and those strings are later concatenated into DOCKER_ARGS and processed by Bash eval during build, deploy, or run operations. Shell command substitutions in the stored values are interpreted on the host, allowing arbitrary command execution with the privileges of the dokku operating-system user. This issue is fixed in version 0.38.25.