{"id":"GHSA-h97m-ww89-6jmq","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.","aliases":["CVE-2024-12224","RUSTSEC-2024-0421"],"modified":"2026-07-17T21:13:05.211452124Z","published":"2024-12-09T20:41:10Z","database_specific":{"github_reviewed_at":"2024-12-09T20:41:10Z","nvd_published_at":"2025-05-30T02:15:19Z","cwe_ids":["CWE-1289","CWE-697"],"severity":"MODERATE","github_reviewed":true},"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"}],"affected":[{"package":{"name":"idna","ecosystem":"crates.io","purl":"pkg:cargo/idna"},"ranges":[{"type":"SEMVER","events":[{"introduced":"0"},{"fixed":"1.0.0"}]}],"database_specific":{"source":"https://github.com/github/advisory-database/blob/main/advisories/github-reviewed/2024/12/GHSA-h97m-ww89-6jmq/GHSA-h97m-ww89-6jmq.json"}}],"schema_version":"1.9.0","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"}]}