CVE-2025-32963

MinIO Operator STS is a native IAM Authentication for Kubernetes. Prior to version 7.1.0, if no audiences are provided for the spec.audiences field, the default will be of the Kubernetes apiserver. Without scoping, it can be replayed to other internal systems, which may unintentionally trust it. This issue has been patched in version 7.1.0.

MinIO Operator STS is a native IAM Authentication for Kubernetes. Prior to version 7.1.0, if no audiences are provided for the spec.audiences field, the default will be of the Kubernetes apiserver. Without scoping, it can be replayed to other internal systems, which may unintentionally trust it. This issue has been patched in version 7.1.0.

Prevent token leakage / privilege escalation

MinIO Operator STS: A Quick Overview

MinIO Operator STS is a native IAM Authentication for Kubernetes. MinIO Operator offers support for Secure Tokens (a.k.a. STS) which are a form of temporary access credentials for your MinIO Tenant. In essence, this allows you to control access to your MinIO tenant from your applications without having to explicitly create credentials for each application.

For an application to gain access into a MinIO Tenant, a PolicyBinding resource is required, granting explicit access to the applications by validating the kubernetes Service Account authorization token.

The service account token is validated as follows:

1. The application calls AssumeRoleWithWebIdentity API MinIO Operator provides.
2. MinIO Operator verifies the Service Account token agains the kubernetes API using the TokenReview API
3. MinIO Operator reviews the TokenReviewResult confirms if the token is a valid token and the user is authenticated.
4. MinIO Operator validates the service account has PolicyBinding in the Tenant namespace.
5. MinIO Operator gets the PolicyBinding
6. MinIO Operator calls the AssumeRole API in the MinIO Tenant
7. MinIO Operator obtains temporary credentials (STS).
8. MinIO Operator return temporary Credentials to the requester application.
9. The applicaiton consumes Object Storage using the temporary credentials.

Understanding Audiences in Kubernetes TokenReview

In step 2 the TokenReview API call attempts to authenticate a token to a known user, TokenReviewStatus is the result of the TokenReview request.

Audiences are audience identifiers chosen by the authenticator that are compatible with both the TokenReview and token.

An identifier is any identifier in the intersection of the TokenReviewSpec audiences and the token's audiences.

A client of the TokenReview API that sets the spec.audiences field should validate that a compatible audience identifier is returned in the status.audiences field to ensure that the TokenReview server is audience aware. If no audiences are provided, the audience will default to the audience of the Kubernetes apiserver.

Solution: Properly Issuing and Using Audience-Specific ServiceAccount Tokens

This PR ensures the Operator STS service request the Service Account JWT to belong to the audiencests.min.io in the TokenReviewRequest.

This PR ensures the examples and documentation provided guides in how to create Service accounts with "disabled auto mount services tokens", by doing this the pods where the service account is used no longer mounts the service account automatically in the path /var/run/secrets/kubernetes.io/serviceaccount.

For illustrative purposes, here is how you disable auto mount of service account tokens at the service account level.

apiVersion: v1
kind: ServiceAccount
metadata:
  namespace: namespace-name
  name: service-account name
automountServiceAccountToken: false

Additionally documentation and examples show how to request an audience-specific token with audience sts.min.io, by asking for an ServiceAccount Token to be audience specific.

For illustrative purposes, here is how you request an audience specific service account token in a pod:

apiVersion: batch/v1
kind: Job
metadata:
  name: job-name
  namespace: job-namespace
spec:
  template:
    spec:
      serviceAccountName: service-account-name
      volumes:
        - name: sa-token
          projected:
            sources:
              - serviceAccountToken:
                  audience: "sts.min.io"
                  expirationSeconds: 86400
      …

MinIO Operator STS is a native IAM Authentication for Kubernetes. Prior to version 7.1.0, if no audiences are provided for the spec.audiences field, the default will be of the Kubernetes apiserver. Without scoping, it can be replayed to other internal systems, which may unintentionally trust it. This issue has been patched in version 7.1.0.

MinIO Operator STS is a native IAM Authentication for Kubernetes. Prior to version 7.1.0, if no audiences are provided for the spec.audiences field, the default will be of the Kubernetes apiserver. Without scoping, it can be replayed to other internal systems, which may unintentionally trust it. This issue has been patched in version 7.1.0.

Prevent token leakage / privilege escalation

MinIO Operator STS: A Quick Overview

MinIO Operator STS is a native IAM Authentication for Kubernetes. MinIO Operator offers support for Secure Tokens (a.k.a. STS) which are a form of temporary access credentials for your MinIO Tenant. In essence, this allows you to control access to your MinIO tenant from your applications without having to explicitly create credentials for each application.

For an application to gain access into a MinIO Tenant, a PolicyBinding resource is required, granting explicit access to the applications by validating the kubernetes Service Account authorization token.

The service account token is validated as follows:

1. The application calls AssumeRoleWithWebIdentity API MinIO Operator provides.
2. MinIO Operator verifies the Service Account token agains the kubernetes API using the TokenReview API
3. MinIO Operator reviews the TokenReviewResult confirms if the token is a valid token and the user is authenticated.
4. MinIO Operator validates the service account has PolicyBinding in the Tenant namespace.
5. MinIO Operator gets the PolicyBinding
6. MinIO Operator calls the AssumeRole API in the MinIO Tenant
7. MinIO Operator obtains temporary credentials (STS).
8. MinIO Operator return temporary Credentials to the requester application.
9. The applicaiton consumes Object Storage using the temporary credentials.

Understanding Audiences in Kubernetes TokenReview

In step 2 the TokenReview API call attempts to authenticate a token to a known user, TokenReviewStatus is the result of the TokenReview request.

Audiences are audience identifiers chosen by the authenticator that are compatible with both the TokenReview and token.

An identifier is any identifier in the intersection of the TokenReviewSpec audiences and the token's audiences.

A client of the TokenReview API that sets the spec.audiences field should validate that a compatible audience identifier is returned in the status.audiences field to ensure that the TokenReview server is audience aware. If no audiences are provided, the audience will default to the audience of the Kubernetes apiserver.

Solution: Properly Issuing and Using Audience-Specific ServiceAccount Tokens

This PR ensures the Operator STS service request the Service Account JWT to belong to the audiencests.min.io in the TokenReviewRequest.

This PR ensures the examples and documentation provided guides in how to create Service accounts with "disabled auto mount services tokens", by doing this the pods where the service account is used no longer mounts the service account automatically in the path /var/run/secrets/kubernetes.io/serviceaccount.

For illustrative purposes, here is how you disable auto mount of service account tokens at the service account level.

apiVersion: v1
kind: ServiceAccount
metadata:
  namespace: namespace-name
  name: service-account name
automountServiceAccountToken: false

Additionally documentation and examples show how to request an audience-specific token with audience sts.min.io, by asking for an ServiceAccount Token to be audience specific.

For illustrative purposes, here is how you request an audience specific service account token in a pod:

apiVersion: batch/v1
kind: Job
metadata:
  name: job-name
  namespace: job-namespace
spec:
  template:
    spec:
      serviceAccountName: service-account-name
      volumes:
        - name: sa-token
          projected:
            sources:
              - serviceAccountToken:
                  audience: "sts.min.io"
                  expirationSeconds: 86400
      …

Minio Operator uses Kubernetes apiserver audience for AssumeRoleWithWebIdentity STS in github.com/minio/operator.

NOTE: The source advisory for this report contains additional versions that could not be automatically mapped to standard Go module versions.

(If this is causing false-positive reports from vulnerability scanners, please suggest an edit to the report.)

The additional affected modules and versions are: github.com/minio/operator before v7.1.0.

These are all security issues fixed in the govulncheck-vulndb-0.0.20250422T181640-1.1 package on the GA media of openSUSE Tumbleweed.