GHSA-653X-RHRR-H9H8
Vulnerability from github – Published: 2026-09-22 09:31 – Updated: 2026-09-22 18:33Net::IDN::UTS46 versions before 2.590 for Perl allow CPU exhaustion via quadratic punycode encoding of an overlong label before the length check in to_ascii.
to_ascii punycode encodes each label and only then applies the 63-byte DNS limit. encode_punycode in both backends follows the sample implementation in RFC 3492, whose outer loop runs once per distinct non-ASCII code point and scans the whole input each round, so a label of distinct non-ASCII characters costs the square of its length before the limit rejects it. Every ASCII conversion in the distribution, including domain_to_ascii and email_to_ascii, goes through to_ascii.
{
"affected": [],
"aliases": [
"CVE-2026-87081"
],
"database_specific": {
"cwe_ids": [
"CWE-407"
],
"github_reviewed": false,
"github_reviewed_at": null,
"nvd_published_at": "2026-09-22T08:16:40Z",
"severity": "HIGH"
},
"details": "Net::IDN::UTS46 versions before 2.590 for Perl allow CPU exhaustion via quadratic punycode encoding of an overlong label before the length check in to_ascii.\n\nto_ascii punycode encodes each label and only then applies the 63-byte DNS limit. encode_punycode in both backends follows the sample implementation in RFC 3492, whose outer loop runs once per distinct non-ASCII code point and scans the whole input each round, so a label of distinct non-ASCII characters costs the square of its length before the limit rejects it. Every ASCII conversion in the distribution, including domain_to_ascii and email_to_ascii, goes through to_ascii.",
"id": "GHSA-653x-rhrr-h9h8",
"modified": "2026-09-22T18:33:28Z",
"published": "2026-09-22T09:31:13Z",
"references": [
{
"type": "ADVISORY",
"url": "https://nvd.nist.gov/vuln/detail/CVE-2026-87081"
},
{
"type": "WEB",
"url": "https://github.com/robrwo/Net-IDN-Encode/commit/5ac3315131264670efcd3a29857b651506dfee8e.patch"
},
{
"type": "WEB",
"url": "https://github.com/robrwo/Net-IDN-Encode/commit/ea34f812d7dc67f3b211f4d92e74c6a7e24d764a.patch"
},
{
"type": "WEB",
"url": "https://metacpan.org/release/PJCJ/Net-IDN-Encode-2.590-TRIAL/changes"
},
{
"type": "WEB",
"url": "http://www.openwall.com/lists/oss-security/2026/09/22/16"
}
],
"schema_version": "1.4.0",
"severity": [
{
"score": "CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:N/I:N/A:H",
"type": "CVSS_V3"
}
]
}
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