CVE-2022-39321

CVE-2022-39321 is a high-severity vulnerability in Github Runner with a CVSS 3.x base score of 8.8. It is not currently listed as actively exploited by CISA, and its EPSS exploit-prediction score is low. The underlying weakness is classified as CWE-78.

Key facts

Description

GitHub Actions Runner is the application that runs a job from a GitHub Actions workflow. 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 in versions prior to 2.296.2, 2.293.1, 2.289.4, 2.285.2, and 2.283.4 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. The Actions Runner has been patched, both on `github.com` and hotfixes for GHES and GHAE customers in versions 2.296.2, 2.293.1, 2.289.4, 2.285.2, and 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. As a workaround, users may consider removing any container actions, job containers, or service containers from their jobs until they are able to upgrade their runner versions.

Frequently asked questions

What is CVE-2022-39321?
GitHub Actions Runner is the application that runs a job from a GitHub Actions workflow. 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 in versions prior to 2.296.2, 2.293.1, 2.289.4, 2.285.2, and 2.283.4 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. The Actions Runner has been patched, both on `github.com` and hotfixes for GHES and GHAE customers in versions 2.296.2, 2.293.1, 2.289.4, 2.285.2, and 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. As a workaround, users may consider removing any container actions, job containers, or service containers from their jobs until they are able to upgrade their runner versions.
How severe is CVE-2022-39321?
CVE-2022-39321 has a CVSS 3.x base score of 8.8, rated high severity. It is exploitable over network with low attack complexity, requires low privileges and no user interaction. Impact on confidentiality is high, integrity high, and availability high.
Is CVE-2022-39321 being actively exploited?
It is not currently listed in CISA's KEV catalog. Its EPSS exploit-prediction score is 1% (71st percentile), an estimate of the probability of exploitation in the next 30 days.
What products are affected by CVE-2022-39321?
CVE-2022-39321 affects Github Runner. See the affected-products list for the exact vulnerable versions.
How do I fix CVE-2022-39321?
Review the linked vendor and NVD advisories for patched versions and mitigations, then upgrade or apply the recommended workaround. Given its high severity, prioritise patching exposed systems.
When was CVE-2022-39321 published?
CVE-2022-39321 was published on 2022-10-25 and last updated on 2026-06-17.

References

Affected products (1)

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