CVE-2021-41254 — HIGH (8.8)

Q: How severe is CVE-2021-41254?

CVE-2021-41254 has been rated HIGH with a CVSS base score of 8.8/10. Review the CVSS metrics above for detailed severity breakdown.

Q: Is there a patch for CVE-2021-41254?

Check the references section above for vendor advisories and patch information. Affected products include: Fluxcd Kustomize-Controller.

Vulnerability Description

kustomize-controller is a Kubernetes operator, specialized in running continuous delivery pipelines for infrastructure and workloads defined with Kubernetes manifests and assembled with Kustomize. Users that can create Kubernetes Secrets, Service Accounts and Flux Kustomization objects, could execute commands inside the kustomize-controller container by embedding a shell script in a Kubernetes Secret. This can be used to run `kubectl` commands under the Service Account of kustomize-controller, thus allowing an authenticated Kubernetes user to gain cluster admin privileges. In affected versions multitenant environments where non-admin users have permissions to create Flux Kustomization objects are affected by this issue. This vulnerability was fixed in kustomize-controller v0.15.0 (included in flux2 v0.18.0) released on 2021-10-08. Starting with v0.15, the kustomize-controller no longer executes shell commands on the container OS and the `kubectl` binary has been removed from the container image. To prevent the creation of Kubernetes Service Accounts with `secrets` in namespaces owned by tenants, a Kubernetes validation webhook such as Gatekeeper OPA or Kyverno can be used.

CVSS Score

8.8

HIGH

CVSS:3.1/AV:N/AC:L/PR:L/UI:N/S:U/C:H/I:H/A:H

Attack Vector

NETWORK

Attack Complexity

LOW

Privileges Required

LOW

User Interaction

NONE

Scope

UNCHANGED

Confidentiality

HIGH

Integrity

HIGH

Availability

HIGH

Affected Products

Vendor	Product	Versions
Fluxcd	Kustomize-Controller	< 0.15.0

Related Weaknesses (CWE)

CWE-78

References

https://github.com/fluxcd/kustomize-controller/security/advisories/GHSA-35rf-v2jExploitMitigationThird Party Advisory
https://github.com/fluxcd/kustomize-controller/security/advisories/GHSA-35rf-v2jExploitMitigationThird Party Advisory

FAQ

What is CVE-2021-41254?

CVE-2021-41254 is a vulnerability with a CVSS score of 8.8 (HIGH). kustomize-controller is a Kubernetes operator, specialized in running continuous delivery pipelines for infrastructure and workloads defined with Kubernetes manifests and assembled with Kustomize. Use...

How severe is CVE-2021-41254?

CVE-2021-41254 has been rated HIGH with a CVSS base score of 8.8/10. Review the CVSS metrics above for detailed severity breakdown.

Is there a patch for CVE-2021-41254?

Check the references section above for vendor advisories and patch information. Affected products include: Fluxcd Kustomize-Controller.