CVE-2026-49822: Fission Cross-namespace Event Leakage Vulnerability

{
  "schema_version" : "1.4.0",
  "id" : "GHSA-gc3j-79f2-7vvw",
  "modified" : "2026-06-30T18:16:03Z",
  "published" : "2026-06-30T18:16:03Z",
  "aliases" : [ "CVE-2026-49822" ],
  "summary" : "Fission: Cross-namespace event leakage via KubernetesWatchTrigger allows persistent tenant surveillance",
  "details" : "### Summary\n\nA low-privilege developer who could create a `KubernetesWatchTrigger` (KWT) in their own namespace was able to establish a persistent surveillance channel over any other namespace.\n\n### Details\n\nTwo independent flaws compounded:\n\n1. `pkg/kubewatcher/kubewatcher.go::createKubernetesWatch` used `w.Spec.Namespace` (user-controlled) directly as the Watch target without checking it against `w.Namespace` (the KWT's own namespace). `kubewatcher` established the Watch\nusing its cluster-scoped service account and serialized every Pod/Service/Job change event as full JSON over HTTP POST to the attacker's function.\n2. The validating webhook (`pkg/webhook/kuberneteswatchtrigger.go`) registered `verbs=create` only, so `update`/`patch` requests bypassed validation entirely.\n\nA separate leak: an empty `spec.namespace` resolved to **all namespaces** via the controller's default, letting an attacker omit the field to surveil the entire cluster.\n\n### Impact\n\nA tenant with `kuberneteswatchtriggers.fission.io/create` could continuously receive full event payloads for Pods, Services, and Jobs in any namespace — a persistent cross-tenant surveillance channel requiring no additional privileges.\n\n### Fix\n\nFixed in [#3379](https://github.com/fission/fission/pull/3379) and released in [v1.24.0](https://github.com/fission/fission/releases/tag/v1.24.0).\n\n- The validating webhook marker is extended to `verbs=create;update`.\n- `Validate` rejects `KubernetesWatchTrigger.spec.namespace != metadata.namespace`.\n- A controller guard in `createKubernetesWatch` rejects cross-namespace targets that bypass admission and coerces an empty `Spec.Namespace` to the trigger's own namespace.\n\n### Behavioural change\n\nKubernetesWatchTriggers with an unset `spec.namespace` now watch only their own namespace instead of all namespaces. Anyone relying on the previous all-namespaces behaviour must create a separate KWT per namespace.",
  "severity" : [ {
    "type" : "CVSS_V3",
    "score" : "CVSS:3.1/AV:N/AC:L/PR:L/UI:N/S:C/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-gc3j-79f2-7vvw"
  }, {
    "type" : "ADVISORY",
    "url" : "https://nvd.nist.gov/vuln/detail/CVE-2026-49822"
  }, {
    "type" : "WEB",
    "url" : "https://github.com/fission/fission/pull/3379"
  }, {
    "type" : "WEB",
    "url" : "https://github.com/fission/fission/commit/e2b92663499f4dc3a1e2d38178f39c3c65e0134a"
  }, {
    "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-284", "CWE-862" ],
    "severity" : "HIGH",
    "github_reviewed" : true,
    "github_reviewed_at" : "2026-06-30T18:16:03Z",
    "nvd_published_at" : "2026-06-10T18:17:10Z"
  }
}