NSEC3 closest-encloser proof validation enters unbounded loop on cross-zone responses

{
  "id": "2b7e7583cf6cefaaccd10691522147a5f092301827f662e94a65c0952225b519",
  "url": "https://osv.dev/vulnerability/RUSTSEC-2026-0120",
  "method": "structured",
  "payload": {
    "kind": "advisory",
    "title": "NSEC3 closest-encloser proof validation enters unbounded loop on cross-zone responses",
    "summary": "The NSEC3 closest-encloser proof validation in `hickory-net`'s `DnssecDnsHandle` walks from the QNAME up to the SOA owner name, building a list of candidate encloser names. The iterator used assumes the QNAME is a descendant of the SOA owner, terminating only when the current candidate equals the SOA name. When the SOA in a response's authority section is not an ancestor of the QNAME, the loop stalls at the DNS root and never terminates, repeatedly calling `Name::base_name()` and pushing newly allocated `Name` and hashed-name entries into the candidate `Vec`. The bug is reachable by any caller of `DnssecDnsHandle` — including the resolver, recursor, and client — when built with the `dnssec-ring` or `dnssec-aws-lc-rs` feature and configured to perform DNSSEC validation. It is triggered while validating a NoData or NXDomain response whose authority section contains an SOA record from a zone other than an ancestor of the QNAME, on a code path that requires NSEC3 closest-encloser proof. In practice this can be reached through an insecure CNAME chain that crosses zone boundaries into a DNSSEC-signed zone returning NoData, but the minimum condition is just a mismatched SOA owner on a response requiring NSEC3 validation. A `debug_assert_ne!(name, Name::root())` guards the loop body, so debug builds abort with a panic on the first iteration past the root. Release builds compile the assertion out and run the loop unbounded, allocating until the process exhausts available memory (OOM).",
    "evidence": "osv:RUSTSEC-2026-0120",
    "products": [
      {
        "name": {
          "value": "hickory-net",
          "evidence": "/affected/0/package/name"
        },
        "prerequisites": [],
        "fixed_versions": [
          {
            "value": "0.26.1",
            "evidence": "/affected/0/ranges"
          }
        ],
        "affected_versions": []
      }
    ],
    "severity": "unknown",
    "structured": {
      "id": "RUSTSEC-2026-0120",
      "aliases": [
        "GHSA-3v94-mw7p-v465",
        "RUSTSEC-2026-0118",
        "RUSTSEC-2026-0120"
      ],
      "affected": [
        {
          "ranges": [
            {
              "type": "SEMVER",
              "events": [
                {
                  "introduced": "0.0.0-0"
                },
                {
                  "fixed": "0.26.1"
                }
              ]
            }
          ],
          "package": {
            "name": "hickory-net",
            "purl": "pkg:cargo/hickory-net",
            "ecosystem": "crates.io"
          },
          "database_specific": {
            "cvss": null,
            "source": "https://github.com/rustsec/advisory-db/blob/osv/crates/RUSTSEC-2026-0120.json",
            "categories": [
              "denial-of-service"
            ],
            "informational": null
          },
          "ecosystem_specific": {
            "affects": {
              "os": [],
              "arch": [],
              "functions": []
            },
            "affected_functions": null
          }
        }
      ],
      "modified": "2026-10-12T18:00:09.238308824Z",
      "provider": "osv",
      "references": [
        "https://crates.io/crates/hickory-net",
        "https://rustsec.org/advisories/RUSTSEC-2026-0120.html",
        "https://github.com/hickory-dns/hickory-dns/pull/3597"
      ],
      "provider_metadata": {
        "license": "CC-BY-4.0"
      }
    },
    "related_cves": [],
    "security_relevant": true,
    "severity_evidence": null
  },
  "source_id": "core-osv",
  "document_id": 306396,
  "published_at": "2026-05-01T12:00:00+00:00"
}