CVE-2026-50565: Github.com/fission/fission Fission Builder Pods Auto-mount The Vulnerability

{
  "schema_version" : "1.4.0",
  "id" : "GHSA-8wcj-mfrc-jx5q",
  "modified" : "2026-06-30T18:20:03Z",
  "published" : "2026-06-30T18:20:03Z",
  "aliases" : [ "CVE-2026-50565" ],
  "summary" : "Fission builder pods auto-mount the fission-builder ServiceAccount token in the user-supplied builder container",
  "details" : "### Summary\n\nFission builder pods were created with `ServiceAccountName: fission-builder` and no `AutomountServiceAccountToken: false`, so the kubelet auto-mounted the service-account token into every container in the pod — including the\nuser-supplied builder image.\n\n### Details\n\nThe user controls the builder container image, command, and podspec through `Environment.spec.builder.image` / `.container` / `.podspec`. With the SA token auto-mounted at `/var/run/secrets/kubernetes.io/serviceaccount/token` inside that\n container, any code running there inherited the `fission-builder` identity. The `fission-builder` SA holds namespace-wide `get` on `secrets` and `configmaps` (`pkg/utils/serviceaccount.go`), so the user-controlled builder container\ncould read every Secret in the builder namespace by name.\n\nThis is the buildermgr sibling of GHSA-85g2-pmrx-r49q (CVE-2026-46617), whose fix suppressed the SA-token automount on function runtime pods but did not cover the structurally identical primitive in `pkg/buildermgr/envwatcher.go`.\n\n### Impact\n\nA subject with `create`/`update` on `Environment` CRDs in a namespace observed by the buildermgr could read every Secret and ConfigMap in the builder namespace via the auto-mounted `fission-builder` token.\n\n### Fix\n\nFixed in [#3390](https://github.com/fission/fission/pull/3390) and released in [v1.24.0](https://github.com/fission/fission/releases/tag/v1.24.0). In `createBuilderDeployment`:\n\n- Set pod-level `AutomountServiceAccountToken=false` on the initial PodSpec and add the projected fetcher SA-token volume.\n- Re-clamp `AutomountServiceAccountToken=false` after every `MergePodSpec` call so a user-supplied podspec cannot restore the kubelet automount.\n- Mount the token via a projected volume on the fetcher sidecar only, so the legitimate build → archive-upload flow keeps its cluster API access.\n\nReuses the projected-volume helpers from `pkg/executor/util/satoken.go` introduced by the GHSA-85g2-pmrx-r49q fix.\n\n### Behavioural change\n\nThe user-supplied builder container no longer receives an auto-mounted SA token. The fetcher sidecar still gets its token via a projected volume.",
  "severity" : [ {
    "type" : "CVSS_V3",
    "score" : "CVSS:3.1/AV:N/AC:L/PR:H/UI:N/S:U/C:H/I:N/A:N"
  } ],
  "affected" : [ {
    "package" : {
      "ecosystem" : "Go",
      "name" : "github.com/fission/fission"
    },
    "ranges" : [ {
      "type" : "ECOSYSTEM",
      "events" : [ {
        "introduced" : "0"
      }, {
        "fixed" : "1.24.0"
      } ]
    } ],
    "database_specific" : {
      "last_known_affected_version_range" : "<= 1.23.0"
    }
  } ],
  "references" : [ {
    "type" : "WEB",
    "url" : "https://github.com/fission/fission/security/advisories/GHSA-8wcj-mfrc-jx5q"
  }, {
    "type" : "ADVISORY",
    "url" : "https://nvd.nist.gov/vuln/detail/CVE-2026-50565"
  }, {
    "type" : "WEB",
    "url" : "https://github.com/fission/fission/pull/3390"
  }, {
    "type" : "WEB",
    "url" : "https://github.com/fission/fission/commit/8fa799417c77ce8a0189d9858bfe11ece29b84a6"
  }, {
    "type" : "PACKAGE",
    "url" : "https://github.com/fission/fission"
  }, {
    "type" : "WEB",
    "url" : "https://github.com/fission/fission/releases/tag/v1.24.0"
  } ],
  "database_specific" : {
    "cwe_ids" : [ "CWE-250", "CWE-269", "CWE-538" ],
    "severity" : "MODERATE",
    "github_reviewed" : true,
    "github_reviewed_at" : "2026-06-30T18:20:03Z",
    "nvd_published_at" : "2026-06-10T18:17:12Z"
  }
}