Apache CloudStack CKS API Key Leak (v4.19.3 <4.20.1.0)
CVE-2025-26521 Published on June 10, 2025
Apache CloudStack: CKS cluster in project exposes user API keys
When an Apache CloudStack user-account creates a CKS-based Kubernetes cluster in a project, the API key and the secret key of the 'kubeadmin' user of the caller account are used to create the secret config in the CKS-based Kubernetes cluster. A member of the project who can access the CKS-based Kubernetes cluster, can also access the API key and secret key of the 'kubeadmin' user of the CKS cluster's creator's account. An attacker who's a member of the project can exploit this to impersonate and perform privileged actions that can result in complete compromise of the confidentiality, integrity, and availability of resources owned by the creator's account.
CKS users are recommended to upgrade to version 4.19.3.0 or 4.20.1.0, which fixes this issue.Updating Existing Kubernetes Clusters in ProjectsA service account should be created for each project to provide limited access specifically for Kubernetes cluster providers and autoscaling. Follow the steps below to create a new service account, update the secret inside the cluster, and regenerate existing API and service keys:1. Create a New Service AccountCreate a new account using the role "Project Kubernetes Service Role" with the following details:
Account Name
kubeadmin-<FIRST_EIGHT_CHARACTERS_OF_PROJECT_ID>
First Name
Kubernetes
Last Name
Service User
Account Type
0 (Normal User)
Role ID
<ID_OF_SERVICE_ROLE>
2. Add the Service Account to the ProjectAdd this account to the project where the Kubernetes cluster(s) are hosted.
3. Generate API and Secret KeysGenerate API Key and Secret Key for the default user of this account.
4. Update the CloudStack Secret in the Kubernetes ClusterCreate a temporary file `/tmp/cloud-config` with the following data:
api-url = <API_URL> # For example: <MS_URL>/client/api
api-key = <SERVICE_USER_API_KEY>
secret-key = <SERVICE_USER_SECRET_KEY>
project-id = <PROJECT_ID>
Delete the existing secret using kubectl and Kubernetes cluster config:
./kubectl --kubeconfig kube.conf -n kube-system delete secret cloudstack-secret
Create a new secret using kubectl and Kubernetes cluster config:
./kubectl --kubeconfig kube.conf -n kube-system create secret generic cloudstack-secret --from-file=/tmp/cloud-config
Remove the temporary file:
rm /tmp/cloud-config5. Regenerate API and Secret KeysRegenerate the API and secret keys for the original user account that was used to create the Kubernetes cluster.
Vulnerability Analysis
CVE-2025-26521 can be exploited with network access, and requires small amount of user privileges. This vulnerability is considered to have a low attack complexity. The potential impact of an exploit of this vulnerability is considered to have a high impact on confidentiality and integrity, and no impact on availability.
Weakness Type
What is an Information Disclosure Vulnerability?
The product exposes sensitive information to an actor that is not explicitly authorized to have access to that information.
CVE-2025-26521 has been classified to as an Information Disclosure vulnerability or weakness.
Products Associated with CVE-2025-26521
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Affected Versions
Apache Software Foundation Apache CloudStack:- Version 4.17.0.0 and below 4.19.3.0 is affected.
- Version 4.20.0.0 and below 4.20.1.0 is affected.
Exploit Probability
EPSS (Exploit Prediction Scoring System) scores estimate the probability that a vulnerability will be exploited in the wild within the next 30 days. The percentile shows you how this score compares to all other vulnerabilities.