Summary
Rancher cloud credentials can be used through proxy API by users without access
Full technical description
A vulnerability was discovered in Rancher 2.2.0 through the aforementioned patched versions, where cloud credentials weren't being properly validated through the Rancher API. Specifically through a proxy designed to communicate with cloud providers. Any Rancher user that was logged-in and aware of a cloud-credential ID that was valid for a given cloud provider, could call that cloud provider's API through the proxy API, and the cloud-credential would be attached. The exploit is limited to valid Rancher users. There is not a direct mitigation outside of upgrading to the patched Rancher versions.
Impact
CVE-2021-25320 has a CVSS score of 9.9 (Critical). 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 (2.4.16, 2.5.9); upgrading removes the vulnerable code path.
Affected versions
Security releases
Kodem intelligence
Severity tells you how bad this could be in the worst case. It does not tell you whether you are exposed. Exploitability and impact are functions of runtime truth: whether the vulnerable code is present, reachable, and actually executes in your application. A vulnerable package can sit in your dependency tree and never run.
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. Kodem's runtime-powered SCA identifies whether this CVE is reachable in your applications.
Already deployed Kodem?
See it in your environmentNew to Kodem? Get a demo →Remediation advice
github.com/rancher/rancher to 2.4.16 or later; github.com/rancher/rancher to 2.5.9 or later
Kodem Kai can prioritize this vulnerability in your dependency tree and generate a fix recommendation.
Frequently Asked Questions
- What is CVE-2021-25320? CVE-2021-25320 is a critical-severity security vulnerability in github.com/rancher/rancher (go), affecting versions >= 2.2.0, < 2.4.16. It is fixed in 2.4.16, 2.5.9.
- How severe is CVE-2021-25320? CVE-2021-25320 has a CVSS score of 9.9 (Critical). 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.
- Which versions of github.com/rancher/rancher are affected by CVE-2021-25320? github.com/rancher/rancher (go) versions >= 2.2.0, < 2.4.16 is affected.
- Is there a fix for CVE-2021-25320? Yes. CVE-2021-25320 is fixed in 2.4.16, 2.5.9. Upgrade to this version or later.
- Is CVE-2021-25320 exploitable, and should I be worried? Whether CVE-2021-25320 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
- What actually determines whether CVE-2021-25320 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.
- How do I fix CVE-2021-25320?
- Upgrade
github.com/rancher/rancherto 2.4.16 or later - Upgrade
github.com/rancher/rancherto 2.5.9 or later
- Upgrade