CVE-2026-49823: Fission Cross-namespace Package Read Vulnerability

{
  "schema_version" : "1.4.0",
  "id" : "GHSA-3r8v-2xmj-5c39",
  "modified" : "2026-06-30T18:16:33Z",
  "published" : "2026-06-30T18:16:33Z",
  "aliases" : [ "CVE-2026-49823" ],
  "summary" : "Fission: Cross-namespace Package read via unvalidated PackageRef in Function admission webhook",
  "details" : "### Summary\n\nA Fission Function spec carries three reference types — Secret, ConfigMap, and Package. The first two were namespace-validated by the admission webhook; `PackageRef.Namespace` was not.\n\n### Details\n\nA tenant with `functions.fission.io/create` in their own namespace could set `spec.package.packageref.namespace` to any other namespace. When the function is invoked, the fetcher sidecar reads the victim Package using the\n`fission-fetcher` service account's namespace-wide `get packages` permission and writes its contents to `/userfunc/deployarchive` inside the attacker's pool pod, exposing the victim's source code and any embedded credentials.\n\nThe `fission-fetcher` SA holds `get packages` in every configured function namespace (granted by `charts/fission-all/templates/_function-access-role.tpl`), so the namespace check was the only barrier between the attacker and any\nin-cluster Fission Package.\n\n### Impact\n\nA function author in one namespace could read the deployment archive — and therefore the source code and embedded secrets — of any Package in any other namespace.\n\n### Fix\n\nFixed in [#3389](https://github.com/fission/fission/pull/3389) and released in [v1.24.0](https://github.com/fission/fission/releases/tag/v1.24.0).\n\nThe admission webhook (`pkg/webhook/function.go::Validate`) rejects `Function.spec.package.packageref.namespace != metadata.namespace`. An empty namespace remains accepted (controllers default it to the function's namespace). This\nshipped together with the EnvironmentRef cross-namespace check (GHSA-cvw6-gfvv-953q).\n\n### Behavioural change\n\nFunctions that explicitly set `spec.package.packageref.namespace` to a different namespace are now rejected at admission.",
  "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-3r8v-2xmj-5c39"
  }, {
    "type" : "ADVISORY",
    "url" : "https://nvd.nist.gov/vuln/detail/CVE-2026-49823"
  }, {
    "type" : "WEB",
    "url" : "https://github.com/fission/fission/pull/3389"
  }, {
    "type" : "WEB",
    "url" : "https://github.com/fission/fission/commit/80e7ba55228e1ef426f51353e25d2682ec61de34"
  }, {
    "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-863" ],
    "severity" : "HIGH",
    "github_reviewed" : true,
    "github_reviewed_at" : "2026-06-30T18:16:33Z",
    "nvd_published_at" : "2026-06-10T18:17:10Z"
  }
}