CVE-2025-26521 | 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.

Published: 2025-06-10 Last update: 2025-07-01 Assigner: [email protected] Source: [email protected]

Conclusion & alert: CVE-2025-26521 is rated Moderate Risk (49.4/100): CVSS High severity, with low exploitation likelihood (EPSS 0.25%). Mandatory action: Review affected assets and schedule remediation.

Risk is dynamic; we continuously reassess and refresh what is shown on this page as upstream context changes.

Exploit prediction scoring system (EPSS) score for CVE-2025-26521

EPSS lead: Daily EPSS estimates relative likelihood of exploitation; percentile ranks this CVE among scored vulnerabilities (higher = more severe relative rank).

# Date Old EPSS score New EPSS score Delta (New - Old)
1 2026-04-06 0.05% 0.25% +0.20%
2 2025-11-12 0.04% 0.05% +0.01%
3 2025-11-06 0.04%

Full EPSS history (7 records total)

Common vulnerability scoring system (CVSS) metrics for CVE-2025-26521

CVSS metrics for this CVE.

Base score Version Severity Vector Exploitability Impact Score source
8.1 3.1 HIGH
CVSS:3.1/AV:N/AC:L/PR:L/UI:N/S:U/C:H/I:H/A:N Click to expand
Attack vector (AV:N)
Could be attacked over the internet or any normal routed network—not just someone sitting at the machine.
Attack complexity (AC:L)
Once they can reach the bug, pulling it off is straightforward—no weird race conditions or rare setup.
Privileges required (PR:L)
A normal user session is enough; they don’t have to be admin.
User interaction (UI:N)
Nobody has to click “OK” or open a trap file; it can work without a victim helping.
Scope (S:U)
Damage stays in the same “trust bubble” as the broken component—no big spill into unrelated systems.
Confidentiality (C:H)
Serious risk that confidential data gets exposed in a big way.
Integrity (I:H)
They could widely tamper with or forge data—trust in the data is badly hurt.
Availability (A:N)
Service keeps running; no real outage angle.
2.8 5.2 134c704f-9b21-4f2e-91b3-4a467353bcc0

Weakness enumeration for CVE-2025-26521

Affected software / configurations for CVE-2025-26521

Vendor Product Version Raw CPE
apache cloudstack >= 4.17.0.0, < 4.19.3.0 cpe:2.3:a:apache:cloudstack:*:*:*:*:*:*:*:*
apache cloudstack >= 4.20.0.0, < 4.20.1.0 cpe:2.3:a:apache:cloudstack:*:*:*:*:*:*:*:*

References for CVE-2025-26521

cvelogic Threat Intelligence