GHSA-h97m-ww89-6jmq

Suggest an improvement
Source
https://github.com/advisories/GHSA-h97m-ww89-6jmq
Import Source
https://github.com/github/advisory-database/blob/main/advisories/github-reviewed/2024/12/GHSA-h97m-ww89-6jmq/GHSA-h97m-ww89-6jmq.json
JSON Data
https://api.osv.dev/v1/vulns/GHSA-h97m-ww89-6jmq
Aliases
Related
Published
2024-12-09T20:41:10Z
Modified
2024-12-09T20:57:11.875600Z
Severity
  • 6.3 (Medium) CVSS_V4 - 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 CVSS Calculator
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.

Concretely, 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.

In 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.

Remedy

Upgrade 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.)

When upgrading, please take a moment to read about alternative Unicode back ends for idna.

If you are using Rust earlier than 1.81 in combination with SQLx 0.8.2 or earlier, please also read an issue about combining them with url 2.5.4 and idna 1.0.3.

Additional information

This 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.

Acknowledgements

Thanks to kageshiron for recognizing the security implications of this behavior.

Database specific 
{
    "nvd_published_at": null,
    "cwe_ids": [
        "CWE-697"
    ],
    "severity": "MODERATE",
    "github_reviewed": true,
    "github_reviewed_at": "2024-12-09T20:41:10Z"
}
References

Affected packages

crates.io / idna

Package

Name
idna
View open source insights on deps.dev
Purl
pkg:cargo/idna

Affected ranges

Type
SEMVER
Events
Introduced
0Unknown introduced version / All previous versions are affected
Fixed
1.0.0