CVE-2024-12224: Idna `idna` Accepts Punycode Labels That Vulnerability

{
  "schema_version" : "1.4.0",
  "id" : "GHSA-h97m-ww89-6jmq",
  "modified" : "2025-05-30T15:01:30Z",
  "published" : "2024-12-09T20:41:10Z",
  "aliases" : [ "CVE-2024-12224" ],
  "summary" : "`idna` accepts Punycode labels that do not produce any non-ASCII when decoded",
  "details" : "`idna` 0.5.0 and earlier accepts Punycode labels that do not produce any non-ASCII output, which means that either ASCII labels or the empty root label can be masked such that they appear unequal without IDNA processing or when processed with a different implementation and equal when processed with `idna` 0.5.0 or earlier.\n\nConcretely, `example.org` and `xn--example-.org` become equal after processing by `idna` 0.5.0 or earlier. Also, `example.org.xn--` and `example.org.` become equal after processing by `idna` 0.5.0 or earlier.\n\nIn applications using `idna` (but not in `idna` itself) this may be able to lead to privilege escalation when host name comparison is part of a privilege check and the behavior is combined with a client that resolves domains with such labels instead of treating them as errors that preclude DNS resolution / URL fetching and with the attacker managing to introduce a DNS entry (and TLS certificate) for an `xn--`-masked name that turns into the name of the target when processed by `idna` 0.5.0 or earlier.\n\n## Remedy\n\nUpgrade to `idna` 1.0.3 or later, if depending on `idna` directly, or to `url` 2.5.4 or later, if depending on `idna` via `url`. (This issue was fixed in `idna` 1.0.0, but versions earlier than 1.0.3 are not recommended for other reasons.)\n\nWhen upgrading, please take a moment to read about [alternative Unicode back ends for `idna`](https://docs.rs/crate/idna_adapter/latest).\n\nIf you are using Rust earlier than 1.81 in combination with SQLx 0.8.2 or earlier, please also read an [issue](https://github.com/servo/rust-url/issues/992) about combining them with `url` 2.5.4 and `idna` 1.0.3.\n\n## Additional information\n\nThis issue resulted from `idna` 0.5.0 and earlier implementing the UTS 46 specification literally on this point and the specification having this bug. The specification bug has been fixed in [revision 33 of UTS 46](https://www.unicode.org/reports/tr46/tr46-33.html#Modifications).\n\n## Acknowledgements\n\nThanks to kageshiron for recognizing the security implications of this behavior.",
  "severity" : [ {
    "type" : "CVSS_V4",
    "score" : "CVSS:4.0/AV:N/AC:H/AT:N/PR:N/UI:N/VC:L/VI:L/VA:N/SC:N/SI:N/SA:N"
  } ],
  "affected" : [ {
    "package" : {
      "ecosystem" : "crates.io",
      "name" : "idna"
    },
    "ranges" : [ {
      "type" : "ECOSYSTEM",
      "events" : [ {
        "introduced" : "0"
      }, {
        "fixed" : "1.0.0"
      } ]
    } ]
  } ],
  "references" : [ {
    "type" : "ADVISORY",
    "url" : "https://nvd.nist.gov/vuln/detail/CVE-2024-12224"
  }, {
    "type" : "WEB",
    "url" : "https://bugzilla.mozilla.org/show_bug.cgi?id=1887898"
  }, {
    "type" : "PACKAGE",
    "url" : "https://github.com/servo/rust-url"
  }, {
    "type" : "WEB",
    "url" : "https://rustsec.org/advisories/RUSTSEC-2024-0421.html"
  } ],
  "database_specific" : {
    "cwe_ids" : [ "CWE-1289", "CWE-697" ],
    "severity" : "MODERATE",
    "github_reviewed" : true,
    "github_reviewed_at" : "2024-12-09T20:41:10Z",
    "nvd_published_at" : "2025-05-30T02:15:19Z"
  }
}