CVE-2025-26521

CVE-2025-26521 is a high-severity vulnerability in Apache Cloudstack with a CVSS 3.x base score of 8.1. 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-200.

Key facts

Description

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.

Frequently asked questions

What is CVE-2025-26521?
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.
How severe is CVE-2025-26521?
CVE-2025-26521 has a CVSS 3.x base score of 8.1, 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 none.
Is CVE-2025-26521 being actively exploited?
It is not currently listed in CISA's KEV catalog. Its EPSS exploit-prediction score is 1% (44th percentile), an estimate of the probability of exploitation in the next 30 days.
What products are affected by CVE-2025-26521?
CVE-2025-26521 affects Apache Cloudstack. See the affected-products list for the exact vulnerable versions.
How do I fix CVE-2025-26521?
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.
Does CVE-2025-26521 have an EU (EUVD) identifier?
Yes. CVE-2025-26521 is tracked in the ENISA EU Vulnerability Database (EUVD) as EUVD-2025-18065.
When was CVE-2025-26521 published?
CVE-2025-26521 was published on 2025-06-10 and last updated on 2026-06-17.

References

Affected products (1)

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