CVE-2026-102748: Dgraph Denial of Service Vulnerability

{
  "schema_version" : "1.4.0",
  "id" : "GHSA-qj98-gp63-54xj",
  "modified" : "2026-10-15T20:17:22Z",
  "published" : "2026-10-15T20:17:22Z",
  "aliases" : [ "CVE-2026-102748" ],
  "summary" : "Dgraph: Zero Unauthenticated HTTP Admin removeNode Denial of Service",
  "details" : "### Summary\n\nDgraph `v25.3.8` exposes a Zero HTTP administrative surface that is unauthenticated when port `6080` is reachable.\n\nThe exposed routes include:\n\n- `/state`\n- `/assign`\n- `/removeNode`\n- `/moveTablet`\n\nAn unauthenticated request to `/removeNode?id=1&group=0` on a single-node standalone deployment breaks the Zero control plane and leaves Alpha repeatedly failing to reconnect to `localhost:5080`.\n\n### Details\n\nThe issue exists because Zero administrative HTTP endpoints are registered directly without any authentication or IP-whitelist wrapper.\n\nRelevant code paths:\n\n- `worker/server_state.go:41`\n- `dgraph/cmd/zero/run.go:295-301`\n- `dgraph/cmd/zero/http.go:106-129`\n- `dgraph/cmd/zero/zero.go:475-477`\n\nThe relevant behavior is:\n\n- `disable-admin-http=false` by default\n- `/removeNode` accepts attacker-controlled `id` and `group`\n- `removeNode` forwards those directly into `Server.RemoveNode`\n- for `group=0`, `Server.RemoveNode` immediately calls `ProposePeerRemoval`\n\nThis means a remote unauthenticated caller can directly trigger destructive membership operations if `6080` is exposed.\n\n### PoC\n\n### Read state without authentication\n\n```bash\ncurl -i http://127.0.0.1:6080/state\n```\n\nObserved response included:\n\n- Zero node `id=1`\n- `groupId=0`\n- `leader=true`\n- cluster topology and tablet state\n\n<img width=\"1878\" height=\"810\" alt=\"图片\" src=\"https://github.com/user-attachments/assets/c6a0001c-bcf7-45b6-a301-481f918be98a\" />\n\n### Write-capable route without authentication\n\n```bash\ncurl -i 'http://127.0.0.1:6080/assign?what=nsids&num=1'\n```\n\nObserved response:\n\n```text\nHTTP/1.1 200 OK\n...\n{\"startId\":\"1\", \"endId\":\"1\", \"readOnly\":\"0\"}\n```\n\nThis confirms the admin plane is not merely informational.\n\n<img width=\"1877\" height=\"805\" alt=\"图片\" src=\"https://github.com/user-attachments/assets/caf60927-83ba-495d-8c55-e48343b8a2c7\" />\n\n### Destructive unauthenticated removeNode\n\n```bash\ncurl -i 'http://127.0.0.1:6080/removeNode?id=1&group=0'\n```\n\nObserved result:\n\n```text\ncurl: (52) Empty reply from server\n```\n\n<img width=\"1877\" height=\"806\" alt=\"图片\" src=\"https://github.com/user-attachments/assets/a837c385-1c2d-42b6-a5c9-0d93a974ff4e\" />\n\nImmediately afterward:\n\n```bash\ncurl -i http://127.0.0.1:6080/health\n```\n\nObserved result:\n\n```text\ncurl: (56) Recv failure: Connection reset by peer\n```\n\n<img width=\"786\" height=\"47\" alt=\"图片\" src=\"https://github.com/user-attachments/assets/bd5e977d-d046-4626-b3df-155b141564fa\" />\n\nAlpha health was still locally reachable, but Alpha logs began repeatedly reporting:\n\n```text\ndial tcp [::1]:5080: connect: connection refused\n```\n\n<img width=\"1688\" height=\"197\" alt=\"图片\" src=\"https://github.com/user-attachments/assets/8ae3bb84-65bc-4951-ad32-5e1c3231c894\" />\n\nThis confirms the request reached the destructive path and disrupted the Zero control plane.\n\n### Impact\n\nAny deployment that exposes Zero HTTP on `6080` exposes destructive unauthenticated administrative capabilities.\n\nAn attacker can:\n\n- read cluster topology and control-plane metadata\n- allocate IDs and timestamps\n- invoke destructive membership actions\n- disrupt the Zero control plane\n- indirectly destabilize Alpha nodes that depend on Zero connectivity\n\nThis is a high-value unauthenticated administrative exposure and, in the reproduced case, a practical denial of service against the control plane.",
  "severity" : [ {
    "type" : "CVSS_V4",
    "score" : "CVSS:4.0/AV:N/AC:L/AT:N/PR:N/UI:N/VC:N/VI:H/VA:H/SC:N/SI:N/SA:H"
  } ],
  "affected" : [ {
    "package" : {
      "ecosystem" : "Go",
      "name" : "github.com/dgraph-io/dgraph/v25"
    },
    "ranges" : [ {
      "type" : "ECOSYSTEM",
      "events" : [ {
        "introduced" : "0"
      }, {
        "fixed" : "25.4.0"
      } ]
    } ],
    "database_specific" : {
      "last_known_affected_version_range" : "<= 25.3.8"
    }
  } ],
  "references" : [ {
    "type" : "WEB",
    "url" : "https://github.com/dgraph-io/dgraph/security/advisories/GHSA-qj98-gp63-54xj"
  }, {
    "type" : "ADVISORY",
    "url" : "https://nvd.nist.gov/vuln/detail/CVE-2026-102748"
  }, {
    "type" : "WEB",
    "url" : "https://github.com/dgraph-io/dgraph/commit/c32f6041387fa631dbc057e265b71aec3384ead1"
  }, {
    "type" : "PACKAGE",
    "url" : "https://github.com/dgraph-io/dgraph"
  }, {
    "type" : "WEB",
    "url" : "https://github.com/dgraph-io/dgraph/releases/tag/v25.4.0"
  } ],
  "database_specific" : {
    "cwe_ids" : [ "CWE-306", "CWE-862" ],
    "severity" : "CRITICAL",
    "github_reviewed" : true,
    "github_reviewed_at" : "2026-10-15T20:17:22Z",
    "nvd_published_at" : "2026-10-14T19:17:05Z"
  }
}