Summary
Rancher does not properly specify ApiGroup when creating Kubernetes RBAC resources
A vulnerability was discovered in Rancher versions 2.0 through the aforementioned fixed versions, where users were granted access to resources regardless of the resource's API group. For example Rancher should have allowed users access to apps.catalog.cattle.io, but instead incorrectly gave access to apps.*. Resource affected include:
Downstream clusters:
apiservices
clusters
clusterrepos
persistentvolumes
storageclasses
Rancher management cluster
apprevisions
apps
catalogtemplates
catalogtemplateversions
clusteralertgroups
clusteralertrules
clustercatalogs
clusterloggings
clustermonitorgraphs
clusterregistrationtokens
clusterroletemplatebindings
clusterscans
etcdbackups
nodepools
nodes
notifiers
pipelineexecutions
pipelines
pipelinesettings
podsecuritypolicytemplateprojectbindings
projectalertgroups
projectalertrules
projectcatalogs
projectloggings
projectmonitorgraphs
projectroletemplatebindings
projects
secrets
sourcecodeproviderconfigs
There is not a direct mitigation besides upgrading to the patched Rancher versions.
Impact
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-2021-25318 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 (2.4.16, 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.
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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-2021-25318? CVE-2021-25318 is a high-severity incorrect permission assignment for critical resource vulnerability in github.com/rancher/rancher (go), affecting versions >= 2.0.0, < 2.4.16. It is fixed in 2.4.16, 2.5.9. A file, directory, or other resource is assigned permissions that allow broader access than intended.
- How severe is CVE-2021-25318? CVE-2021-25318 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.
- Which versions of github.com/rancher/rancher are affected by CVE-2021-25318? github.com/rancher/rancher (go) versions >= 2.0.0, < 2.4.16 is affected.
- Is there a fix for CVE-2021-25318? Yes. CVE-2021-25318 is fixed in 2.4.16, 2.5.9. Upgrade to this version or later.
- Is CVE-2021-25318 exploitable, and should I be worried? Whether CVE-2021-25318 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-2021-25318 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-2021-25318?
- Upgrade
github.com/rancher/rancherto 2.4.16 or later - Upgrade
github.com/rancher/rancherto 2.5.9 or later
- Upgrade