CVE-2026-40304: zrok Broken Ownership Check Vulnerability

{
  "schema_version" : "1.4.0",
  "id" : "GHSA-3jpj-v3xr-5h6g",
  "modified" : "2026-04-24T20:49:03Z",
  "published" : "2026-04-16T21:09:23Z",
  "aliases" : [ "CVE-2026-40304" ],
  "summary" : "zrok: Broken ownership check in DELETE /api/v2/unaccess allows non-admin to delete global frontend records",
  "details" : "Summary\nThe unaccess handler (controller/unaccess.go) contains a logical error in its ownership guard: when a frontend record has environment_id = NULL (the marker for admin-created global frontends), the condition short-circuits to false and allows the deletion to proceed without any ownership verification. A non-admin user who knows a global frontend token can call DELETE /api/v2/unaccess with any of their own environment IDs and permanently delete the global frontend, taking down all public shares routed through it.\n\nAttack Vector: Network — the endpoint is a standard HTTP API call.\n\nAttack Complexity: High — successful exploitation requires prior knowledge of a global frontend token. These tokens are not returned to non-admin users by any standard API endpoint; obtaining one requires an out-of-band step (e.g., leaked server logs, admin documentation for a self-hosted instance, or social engineering).\n\nPrivileges Required: Low — a valid user account with at least one registered environment is required; no admin privileges needed.\n\nUser Interaction: None.\n\nScope: Unchanged — the impact stays within the same server instance.\n\nConfidentiality Impact: None — no data is disclosed.\n\nIntegrity Impact: None — no data is improperly modified; the record is deleted (not corrupted).\n\nAvailability Impact: High — deleting a global frontend disrupts every public share routed through it on the instance, constituting a platform-wide availability impact.\n\nAffected Component\ncontroller/unaccess.go — unaccessHandler.Handle (line 56)",
  "severity" : [ {
    "type" : "CVSS_V3",
    "score" : "CVSS:3.1/AV:N/AC:H/PR:L/UI:N/S:U/C:N/I:N/A:H"
  } ],
  "affected" : [ {
    "package" : {
      "ecosystem" : "Go",
      "name" : "github.com/openziti/zrok"
    },
    "ranges" : [ {
      "type" : "ECOSYSTEM",
      "events" : [ {
        "introduced" : "0"
      }, {
        "last_affected" : "1.1.11"
      } ]
    } ]
  }, {
    "package" : {
      "ecosystem" : "Go",
      "name" : "github.com/openziti/zrok/v2"
    },
    "ranges" : [ {
      "type" : "ECOSYSTEM",
      "events" : [ {
        "introduced" : "0"
      }, {
        "fixed" : "2.0.1"
      } ]
    } ]
  } ],
  "references" : [ {
    "type" : "WEB",
    "url" : "https://github.com/openziti/zrok/security/advisories/GHSA-3jpj-v3xr-5h6g"
  }, {
    "type" : "ADVISORY",
    "url" : "https://nvd.nist.gov/vuln/detail/CVE-2026-40304"
  }, {
    "type" : "PACKAGE",
    "url" : "https://github.com/openziti/zrok"
  }, {
    "type" : "WEB",
    "url" : "https://github.com/openziti/zrok/releases/tag/v2.0.1"
  } ],
  "database_specific" : {
    "cwe_ids" : [ "CWE-284", "CWE-863" ],
    "severity" : "MODERATE",
    "github_reviewed" : true,
    "github_reviewed_at" : "2026-04-16T21:09:23Z",
    "nvd_published_at" : "2026-04-17T22:16:32Z"
  }
}