CVE-2026-73499: etcd Watch API Authorization Bypass Vulnerability

{
  "schema_version" : "1.4.0",
  "id" : "GHSA-xg4h-6gfc-h4m8",
  "modified" : "2026-08-12T21:20:37Z",
  "published" : "2026-07-24T22:38:22Z",
  "aliases" : [ "CVE-2026-73499" ],
  "summary" : "etcd: Watch API authorization bypass via open-ended range requests",
  "details" : "### Impact\n_What kind of vulnerability is it? Who is impacted?_\n\nA user granted READ permission on a single, exact key can use the Watch gRPC API with `clientv3.WithFromKey()` (an open-ended, \"from this key to the end of the keyspace\" watch) to receive watch events for every key lexicographically greater than or equal to their permitted key — not just the one key they were granted. \n\nThis is an authorization bypass in etcd's RBAC enforcement for the Watch API; Range/Get and DeleteRange requests are not affected. It only affects clusters with authentication enabled — clusters running without auth already allow unrestricted read access.\n\n### Patches\n_Has the problem been patched? What versions should users upgrade to?_\n\nThis vulnerability is patched in the following versions:\n\n- etcd 3.7.1\n- etcd 3.6.14\n- etcd 3.5.33\n\n### Workarounds\n_Is there a way for users to fix or remediate the vulnerability without upgrading?_\n\nIf upgrading is not immediately possible, the following mitigations reduce exposure:\n\n- Audit READ grants. Any READ grant — even on one key — can be leveraged via Watch to read everything after it. Review who holds READ permissions and revoke/tighten any you wouldn't trust with full read access.\n- Restrict network access. Limit which hosts can reach etcd's client (gRPC) port via firewall rules or network policy, reducing who can attempt exploitation.\n\n### Reporter\n\n- Luis Toro ([@lobuhi](https://github.com/lobuhi) on Github)\n- Anthropic  and Adam Korczynski ([@AdamKorcz](https://github.com/AdamKorcz) on Github)",
  "severity" : [ {
    "type" : "CVSS_V4",
    "score" : "CVSS:4.0/AV:N/AC:L/AT:N/PR:L/UI:N/VC:H/VI:N/VA:N/SC:N/SI:N/SA:N"
  } ],
  "affected" : [ {
    "package" : {
      "ecosystem" : "Go",
      "name" : "go.etcd.io/etcd/v3"
    },
    "ranges" : [ {
      "type" : "ECOSYSTEM",
      "events" : [ {
        "introduced" : "3.7.0-alpha.0"
      }, {
        "fixed" : "3.7.1"
      } ]
    } ]
  }, {
    "package" : {
      "ecosystem" : "Go",
      "name" : "go.etcd.io/etcd/v3"
    },
    "ranges" : [ {
      "type" : "ECOSYSTEM",
      "events" : [ {
        "introduced" : "3.6.0"
      }, {
        "fixed" : "3.6.14"
      } ]
    } ]
  }, {
    "package" : {
      "ecosystem" : "Go",
      "name" : "go.etcd.io/etcd/v3"
    },
    "ranges" : [ {
      "type" : "ECOSYSTEM",
      "events" : [ {
        "introduced" : "0"
      }, {
        "fixed" : "3.5.33"
      } ]
    } ]
  } ],
  "references" : [ {
    "type" : "WEB",
    "url" : "https://github.com/etcd-io/etcd/security/advisories/GHSA-xg4h-6gfc-h4m8"
  }, {
    "type" : "WEB",
    "url" : "https://github.com/etcd-io/etcd/commit/6643f80602461a6095c9b294b6512fd9719bef41"
  }, {
    "type" : "WEB",
    "url" : "https://github.com/etcd-io/etcd/commit/afeaa624da19085b47fb5ccc7c22a8c421bc2eae"
  }, {
    "type" : "WEB",
    "url" : "https://github.com/etcd-io/etcd/commit/e863b001bbf3367003a543aa3099db9892134cd7"
  }, {
    "type" : "PACKAGE",
    "url" : "https://github.com/etcd-io/etcd"
  }, {
    "type" : "WEB",
    "url" : "https://github.com/etcd-io/etcd/releases/tag/v3.5.33"
  }, {
    "type" : "WEB",
    "url" : "https://github.com/etcd-io/etcd/releases/tag/v3.6.14"
  }, {
    "type" : "WEB",
    "url" : "https://github.com/etcd-io/etcd/releases/tag/v3.7.1"
  } ],
  "database_specific" : {
    "cwe_ids" : [ "CWE-863" ],
    "severity" : "HIGH",
    "github_reviewed" : true,
    "github_reviewed_at" : "2026-07-24T22:38:22Z",
    "nvd_published_at" : null
  }
}