GHSA-3v94-mw7p-v465: hickory-proto NSEC3 Closest-encloser Proof Validation Enters Vulnerability

{
  "schema_version" : "1.4.0",
  "id" : "GHSA-3v94-mw7p-v465",
  "modified" : "2026-05-07T02:59:20Z",
  "published" : "2026-05-07T02:59:20Z",
  "aliases" : [ ],
  "summary" : "hickory-proto: NSEC3 closest-encloser proof validation enters unbounded loop on cross-zone responses",
  "details" : "The NSEC3 closest-encloser proof validation in `hickory-proto`'s (0.25.0-alpha.3 ... 0.25.2) and `hickory-net`'s (0.26.0-alpha.1 .. 0.26.0)  `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`.\n\nThe 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.\n\nA `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. A reachable upstream attacker who can return such a response can therefore crash a debug build or exhaust memory on a release build, for the affected configurations.\n\nThe affected code was migrated from `hickory-proto` to `hickory-net` as part of the 0.26.0 release. Hickory DNS recommends that all affected users update to `hickory-net` 0.26.1 for the fix.\n\n### Reporter\n\nDavid Cook, ISRG",
  "severity" : [ {
    "type" : "CVSS_V4",
    "score" : "CVSS:4.0/AV:N/AC:L/AT:N/PR:N/UI:N/VC:N/VI:N/VA:H/SC:N/SI:N/SA:N"
  } ],
  "affected" : [ {
    "package" : {
      "ecosystem" : "crates.io",
      "name" : "hickory-proto"
    },
    "ranges" : [ {
      "type" : "ECOSYSTEM",
      "events" : [ {
        "introduced" : "0.25.0-alpha.3"
      }, {
        "last_affected" : "0.25.2"
      } ]
    } ]
  }, {
    "package" : {
      "ecosystem" : "crates.io",
      "name" : "hickory-net"
    },
    "ranges" : [ {
      "type" : "ECOSYSTEM",
      "events" : [ {
        "introduced" : "0.26.0-alpha.1"
      }, {
        "fixed" : "0.26.1"
      } ]
    } ],
    "database_specific" : {
      "last_known_affected_version_range" : "<= 0.26.0"
    }
  } ],
  "references" : [ {
    "type" : "WEB",
    "url" : "https://github.com/hickory-dns/hickory-dns/security/advisories/GHSA-3v94-mw7p-v465"
  }, {
    "type" : "PACKAGE",
    "url" : "https://github.com/hickory-dns/hickory-dns"
  }, {
    "type" : "WEB",
    "url" : "https://rustsec.org/advisories/RUSTSEC-2026-0118.html"
  }, {
    "type" : "WEB",
    "url" : "https://rustsec.org/advisories/RUSTSEC-2026-0120.html"
  } ],
  "database_specific" : {
    "cwe_ids" : [ "CWE-835" ],
    "severity" : "HIGH",
    "github_reviewed" : true,
    "github_reviewed_at" : "2026-05-07T02:59:20Z",
    "nvd_published_at" : null
  }
}