GHSA-V455-MV2V-5G92

Vulnerability from github – Published: 2026-06-30 18:18 – Updated: 2026-06-30 18:18
VLAI
Summary
Fission Container Executor Function PodSpec Injection Leading to Node Escape
Details

Summary

Fission's Container Executor path lets a tenant supply Function.spec.podspec directly; the executor merges it into the executor-built podspec and creates a Deployment whose pods run the user's container image.

Details

Two flaws compounded:

  1. pkg/apis/core/v1/validation.go::FunctionSpec.Validate only checked that spec.PodSpec != nil when executorType: container; it did not inspect the content of spec.PodSpec.
  2. pkg/executor/util/merge.go::MergePodSpec unconditionally forwarded hostPID, hostNetwork, hostIPC, hostPath volumes, serviceAccountName, and container privileged into the Deployment spec via the container-executor sink (pkg/executor/executortype/container/deployment.go::getDeploymentSpec).

A tenant with only functions.fission.io/create could deploy a Function with a crafted podspec that mounted the host root filesystem and shared host namespaces. The executor — running under its high-privilege SA, which holds deployments/create on the function namespace — created that Deployment on the tenant's behalf, turning Function-create into effective deployments/create with arbitrary pod-security configuration.

This is the Function-CRD sibling of GHSA-gx55-f84r-v3r7 / GHSA-wmgg-3p4h-48x7, with a lower attack threshold: regular function developers typically hold functions/create but not environments/create.

Impact

A tenant with only functions.fission.io/create is escalated to node escape via a privileged, host-namespace pod scheduled by the executor.

Fix

Fixed in #3391 and released in v1.24.0.

  • FunctionSpec.Validate now calls ValidatePodSpecSafety("Function.spec.podspec", spec.PodSpec) after the existing spec.PodSpec == nil check.
  • The Function validating webhook is already registered on verbs=create;update, so it picks up the new validation with no marker change.
  • The same merge-layer strip and per-container sanitize used for the Environment path applies here, since the container-executor sink calls util.MergePodSpec.

See GHSA-gx55-f84r-v3r7 for the detailed fix.

Behavioural change

Functions whose spec.podspec sets host namespaces, hostPath volumes, container privileged/allowPrivilegeEscalation, dangerous Linux capabilities, or a serviceAccountName override are now rejected at admission. Legitimate container-executor functions that set image, command, args, env, resources, nodeSelector, tolerations, affinity, non-hostPath volumes, or volumeMounts are unaffected.

Show details on source website

{
  "affected": [
    {
      "database_specific": {
        "last_known_affected_version_range": "\u003c= 1.23.0"
      },
      "package": {
        "ecosystem": "Go",
        "name": "github.com/fission/fission"
      },
      "ranges": [
        {
          "events": [
            {
              "introduced": "0"
            },
            {
              "fixed": "1.24.0"
            }
          ],
          "type": "ECOSYSTEM"
        }
      ]
    }
  ],
  "aliases": [
    "CVE-2026-50563"
  ],
  "database_specific": {
    "cwe_ids": [
      "CWE-269",
      "CWE-284"
    ],
    "github_reviewed": true,
    "github_reviewed_at": "2026-06-30T18:18:42Z",
    "nvd_published_at": "2026-06-10T18:17:12Z",
    "severity": "CRITICAL"
  },
  "details": "### Summary\n\nFission\u0027s Container Executor path lets a tenant supply `Function.spec.podspec` directly; the executor merges it into the executor-built podspec and creates a Deployment whose pods run the user\u0027s container image.\n\n### Details\n\nTwo flaws compounded:\n\n1. `pkg/apis/core/v1/validation.go::FunctionSpec.Validate` only checked that `spec.PodSpec != nil` when `executorType: container`; it did not inspect the content of `spec.PodSpec`.\n2. `pkg/executor/util/merge.go::MergePodSpec` unconditionally forwarded `hostPID`, `hostNetwork`, `hostIPC`, hostPath volumes, `serviceAccountName`, and container `privileged` into the Deployment spec via the container-executor sink\n(`pkg/executor/executortype/container/deployment.go::getDeploymentSpec`).\n\nA tenant with only `functions.fission.io/create` could deploy a Function with a crafted podspec that mounted the host root filesystem and shared host namespaces. The executor \u2014 running under its high-privilege SA, which holds\n`deployments/create` on the function namespace \u2014 created that Deployment on the tenant\u0027s behalf, turning Function-create into effective `deployments/create` with arbitrary pod-security configuration.\n\nThis is the Function-CRD sibling of GHSA-gx55-f84r-v3r7 / GHSA-wmgg-3p4h-48x7, with a **lower** attack threshold: regular function developers typically hold `functions/create` but not `environments/create`.\n\n### Impact\n\nA tenant with only `functions.fission.io/create` is escalated to node escape via a privileged, host-namespace pod scheduled by the executor.\n\n### Fix\n\nFixed in [#3391](https://github.com/fission/fission/pull/3391) and released in [v1.24.0](https://github.com/fission/fission/releases/tag/v1.24.0).\n\n- `FunctionSpec.Validate` now calls `ValidatePodSpecSafety(\"Function.spec.podspec\", spec.PodSpec)` after the existing `spec.PodSpec == nil` check.\n- The Function validating webhook is already registered on `verbs=create;update`, so it picks up the new validation with no marker change.\n- The same merge-layer strip and per-container sanitize used for the Environment path applies here, since the container-executor sink calls `util.MergePodSpec`.\n\nSee GHSA-gx55-f84r-v3r7 for the detailed fix.\n\n### Behavioural change\n\nFunctions whose `spec.podspec` sets host namespaces, hostPath volumes, container `privileged`/`allowPrivilegeEscalation`, dangerous Linux capabilities, or a `serviceAccountName` override are now rejected at admission. Legitimate\ncontainer-executor functions that set `image`, `command`, `args`, `env`, `resources`, `nodeSelector`, `tolerations`, `affinity`, non-hostPath `volumes`, or `volumeMounts` are unaffected.",
  "id": "GHSA-v455-mv2v-5g92",
  "modified": "2026-06-30T18:18:42Z",
  "published": "2026-06-30T18:18:42Z",
  "references": [
    {
      "type": "WEB",
      "url": "https://github.com/fission/fission/security/advisories/GHSA-v455-mv2v-5g92"
    },
    {
      "type": "ADVISORY",
      "url": "https://nvd.nist.gov/vuln/detail/CVE-2026-50563"
    },
    {
      "type": "WEB",
      "url": "https://github.com/fission/fission/pull/3391"
    },
    {
      "type": "WEB",
      "url": "https://github.com/fission/fission/commit/e484df8460bb4e8026e24210120602aa7f181f64"
    },
    {
      "type": "PACKAGE",
      "url": "https://github.com/fission/fission"
    },
    {
      "type": "WEB",
      "url": "https://github.com/fission/fission/releases/tag/v1.24.0"
    }
  ],
  "schema_version": "1.4.0",
  "severity": [
    {
      "score": "CVSS:3.1/AV:N/AC:L/PR:L/UI:N/S:C/C:H/I:H/A:H",
      "type": "CVSS_V3"
    }
  ],
  "summary": "Fission Container Executor Function PodSpec Injection Leading to Node Escape"
}


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