CVE-2023-23939

Azure/setup-kubectl: Escalation of privilege vulnerability for v3 and lower

Workarounds

If users absolutely cannot upgrade to v3 or higher than they should be extra diligent of the other GitHub actions they are using in a workflow and ensure that their GitHub actions runner is secure.

This vulnerability only impacts versions v2 and lower. An insecure temporary creation of a file allows other actors on the Actions runner to replace the Kubectl binary created by this action because it is world writable. This Kubectl tool installer runs fs.chmodSync(kubectlPath, 777) to set permissions on the Kubectl binary, however, this allows any local user to replace the Kubectl binary. This allows privilege escalation to the user that can also run kubectl, most likely root. This attack is only possible if an attacker somehow breached the GitHub actions runner or if a user is utilizing an Action that maliciously executes this attack.

No impacted customers have been reported.

A file, directory, or other resource is assigned permissions that allow broader access than intended. Typical impact: unauthorized read, modification, or execution of the resource.

CVE-2023-23939 has a CVSS score of 3.0 (Low). The vector is reachable from an adjacent network, 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 (3); upgrading removes the vulnerable code path.

Kodem intelligence

Already deployed Kodem?

This has been fixed and released in all versions v3 and later. 755 permissions are used instead.

1. What is CVE-2023-23939? CVE-2023-23939 is a low-severity incorrect permission assignment for critical resource vulnerability in Azure/setup-kubectl (actions), affecting versions < 3. It is fixed in 3. A file, directory, or other resource is assigned permissions that allow broader access than intended.
2. How severe is CVE-2023-23939? CVE-2023-23939 has a CVSS score of 3.0 (Low). 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 Azure/setup-kubectl are affected by CVE-2023-23939? Azure/setup-kubectl (actions) versions < 3 is affected.
4. Is there a fix for CVE-2023-23939? Yes. CVE-2023-23939 is fixed in 3. Upgrade to this version or later.
5. Is CVE-2023-23939 exploitable, and should I be worried? Whether CVE-2023-23939 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-2023-23939 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-2023-23939? Upgrade Azure/setup-kubectl to 3 or later.