Dokku's cron plugin, before version 0.38.7, parses cron commands from app.json and executes them in the container as the Dokku user. Because the parser does not sanitize shell metacharacters, an attacker who can configure or alter an app.json file can inject shell syntax such as > or ;. The injected command is then run in the container but can escape to the host kernel, allowing the attacker to execute arbitrary commands with Dokku's user privileges. This weakness, classified as CWE‑78 (OS Command Injection), may lead to full compromise of the host if the Dokku user has escalated rights or access to critical services.

The vulnerability affects Dokku deployments running any version prior to 0.38.7. It applies to the Dokku PaaS that uses the cron plugin to manage scheduled tasks via app.json definitions. Users of older Dokku releases should check their version and update accordingly.

The CVSS score of 9.0 indicates high severity. The EPSS score is not available, so current exploitation probability is unknown; however, the issue is not listed in the CISA KEV catalog at present. The likely attack vector is through a compromised or malicious app.json file that defines a cron task. An attacker who can introduce such a file, for example via a repository push or a malicious application deployment, can trigger host‑side command execution as the Dokku user. If the Dokku user has sudo privileges or can access sensitive data, the risk escalates to system compromise.