CVE-2022-39321

Docker Command Escaping in the GitHub Actions Runner

Workarounds

You may want to consider removing any container actions, job containers, or service containers from your jobs until you are able to upgrade your runner versions.

For more information

If you have any questions or comments about this advisory:

• Open an issue in the actions runner

The actions runner invokes the docker cli directly in order to run job containers, service containers, or container actions. A bug in the logic for how the environment is encoded into these docker commands was discovered that allows an input to escape the environment variable and modify that docker command invocation directly. Jobs that use container actions, job containers, or service containers alongside untrusted user inputs in environment variables may be vulnerable.

Untrusted input reaches a shell command, allowing arbitrary commands to run on the host. Typical impact: code execution in the application's environment.

CVE-2022-39321 has a CVSS score of 8.8 (High). The vector is network-reachable, low privileges required, and no user interaction. A CVSS score reflects the worst-case severity of the vulnerability, not your specific exposure. Whether this affects your application depends on whether the vulnerable code is present and reachable in your environment. A fixed version is available (2.296.2, 2.293.1, 2.289.4, 2.285.2, 2.283.4); upgrading removes the vulnerable code path.

Kodem intelligence

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The Actions Runner has been patched, both on github.com and hotfixes for GHES and GHAE customers. Please update to one of the following versions of the runner:

• 2.296.2
• 2.293.1
• 2.289.4
• 2.285.2
• 2.283.4

GHES and GHAE customers may want to patch their instance in order to have their runners automatically upgrade to these new runner versions.

1. What is CVE-2022-39321? CVE-2022-39321 is a high-severity OS command injection vulnerability in actions/runner (actions), affecting versions >= 2.294.0, < 2.296.1. It is fixed in 2.296.2, 2.293.1, 2.289.4, 2.285.2, 2.283.4. Untrusted input reaches a shell command, allowing arbitrary commands to run on the host.
2. How severe is CVE-2022-39321? CVE-2022-39321 has a CVSS score of 8.8 (High). This score reflects the worst-case severity of the vulnerability, not your specific exposure. Whether it represents real risk in your environment depends on whether the vulnerable code is present and reachable.
3. Which versions of actions/runner are affected by CVE-2022-39321? actions/runner (actions) versions >= 2.294.0, < 2.296.1 is affected.
4. Is there a fix for CVE-2022-39321? Yes. CVE-2022-39321 is fixed in 2.296.2, 2.293.1, 2.289.4, 2.285.2, 2.283.4. Upgrade to this version or later.
5. Is CVE-2022-39321 exploitable, and should I be worried? Whether CVE-2022-39321 is exploitable in your environment depends on whether the vulnerable code is present and reachable. A CVSS score is a worst-case rating; it does not account for your specific deployment, configuration, or usage patterns. Kodem, an Intelligent Application Security platform, uses runtime intelligence to show which vulnerabilities actually execute in production, so you can focus on the ones that represent real risk. Get a demo
6. What actually determines whether CVE-2022-39321 is exploitable, and how bad it is? Exploitability and impact are not fixed properties of a CVE. They depend on runtime truth: whether the vulnerable code is present, reachable, and actually executes in your application. A high CVSS score on a dependency that never runs is not the same as real risk. Kodem, an Intelligent Application Security platform, uses runtime intelligence to reveal which vulnerabilities actually execute in production, so teams prioritize the ones that genuinely matter.
7. How do I fix CVE-2022-39321?
   • Upgrade actions/runner to 2.296.2 or later
   • Upgrade actions/runner to 2.293.1 or later
   • Upgrade actions/runner to 2.289.4 or later
   • Upgrade actions/runner to 2.285.2 or later
   • Upgrade actions/runner to 2.283.4 or later