High severity · published Jun 10, 2025
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…
8.1
CVSS
0.7%
EPSS
No
On KEV
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.
CVSS vector
CVSS:3.1/AV:N/AC:L/PR:L/UI:N/S:U/C:H/I:H/A:N
Attack vector
Network
Complexity
Low
Privileges
Low
User interaction
None
Confidentiality
High
Integrity
High
Availability
None
Scope
Unchanged
Exploitation
Is it being used?
Exploit prediction (EPSS)0.7% · higher than 52% of CVEs
Exploited in the wildNo evidence yet
CISA KEVNot listed
Ransomware campaign useNot known
Affected products
Which versions
CL
Cloudstack · Apache
4.17.0.0 before 4.19.3.0; 4.20.0.0 before 4.20.1.0 · source: NVD
References
NVD
https://nvd.nist.gov/vuln/detail/CVE-2025-26521
CVE.org
https://www.cve.org/CVERecord?id=CVE-2025-26521
Vendor Advisory
https://cloudstack.apache.org/blog/cve-advisories-4.19.3.0-4.20.1.0/
Mailing List
https://lists.apache.org/thread/y3qnwn59t8qggtdohv7k7vw39bgb3d60
Broken Link
https://www.shapeblue.com/shapeblue-security-advisory-apache-cloudstack-security-releases-4-19-3-0-and-4-20-1-0/
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