{"dataType": "CVE_RECORD", "dataVersion": "5.2", "cveMetadata": {"cveId": "CVE-2026-19953", "assignerOrgId": "9b29abf9-4ab0-4765-b253-1875cd9b441e", "state": "PUBLISHED", "assignerShortName": "CPANSec", "dateReserved": "2026-08-15T21:13:08.480Z", "datePublished": "2026-08-31T17:29:42.929Z", "dateUpdated": "2026-08-31T17:29:42.929Z"}, "containers": {"cna": {"affected": [{"collectionURL": "https://cpan.org/modules", "defaultStatus": "unaffected", "modules": ["URI"], "packageName": "URI", "packageURL": "pkg:cpan/URI", "programFiles": ["lib/URI/_idna.pm"], "programRoutines": [{"name": "URI::_idna::nameprep"}], "repo": "https://github.com/libwww-perl/URI", "versions": [{"lessThan": "5.36", "status": "affected", "version": "0", "versionType": "custom"}]}], "credits": [{"lang": "en", "type": "finder", "value": "Naseeb Dangi (naseeb0), Nankai University"}], "descriptions": [{"lang": "en", "value": "URI versions before 5.36 for Perl encode non-NFC host names to non-standard punycode labels via missing normalization in nameprep.\n\nnameprep lowercases each host label but performs no Unicode normalization. IDNA requires a label to be normalized to Form C before it is encoded (RFC 5891), so a label that is not already in NFC is encoded to a different A-label than its normalized form. A label built from the precomposed Devanagari sequence U+0958 U+093E encodes to xn--72b5c without normalization but to xn--11b2fg after NFC normalization, and xn--72b5c does not round-trip back to the original label.\n\nAny caller that reads host() from a URI built from untrusted input and uses it for a security decision (an allow or deny list, an SSRF filter, deduplication, a cache key) sees the non-standard label, while a client that fetches the same URL resolves the NFC form, so the check and the fetch can disagree about the host."}], "problemTypes": [{"descriptions": [{"cweId": "CWE-1289", "description": "CWE-1289 Improper Validation of Unsafe Equivalence in Input", "lang": "en", "type": "CWE"}]}], "providerMetadata": {"orgId": "9b29abf9-4ab0-4765-b253-1875cd9b441e", "shortName": "CPANSec", "dateUpdated": "2026-08-31T17:29:42.929Z"}, "references": [{"tags": ["patch"], "url": "https://github.com/libwww-perl/URI/commit/956619a9e94f86d8d2c529b4e06a3674c54a73e7.patch"}, {"tags": ["issue-tracking"], "url": "https://github.com/libwww-perl/URI/pull/191"}, {"tags": ["release-notes"], "url": "https://metacpan.org/release/OALDERS/URI-5.36/changes"}, {"tags": ["technical-description"], "url": "https://www.rfc-editor.org/rfc/rfc5891#section-5.2"}], "solutions": [{"lang": "en", "value": "Upgrade to URI 5.36 or later."}], "source": {"discovery": "UNKNOWN"}, "title": "URI versions before 5.36 for Perl encode non-NFC host names to non-standard punycode labels via missing normalization in nameprep", "x_generator": {"engine": "cpansec-cna-tool 0.1"}}}}

{}

{"affected": [{"affectedData": [{"collectionURL": "https://cpan.org/modules", "defaultStatus": "unaffected", "modules": ["URI"], "packageName": "URI", "packageURL": "pkg:cpan/URI", "programFiles": ["lib/URI/_idna.pm"], "programRoutines": [{"name": "URI::_idna::nameprep"}], "repo": "https://github.com/libwww-perl/URI", "versions": [{"lessThan": "5.36", "status": "affected", "version": "0", "versionType": "custom"}]}], "source": "9b29abf9-4ab0-4765-b253-1875cd9b441e"}], "cveTags": [], "descriptions": [{"lang": "en", "value": "URI versions before 5.36 for Perl encode non-NFC host names to non-standard punycode labels via missing normalization in nameprep.\n\nnameprep lowercases each host label but performs no Unicode normalization. IDNA requires a label to be normalized to Form C before it is encoded (RFC 5891), so a label that is not already in NFC is encoded to a different A-label than its normalized form. A label built from the precomposed Devanagari sequence U+0958 U+093E encodes to xn--72b5c without normalization but to xn--11b2fg after NFC normalization, and xn--72b5c does not round-trip back to the original label.\n\nAny caller that reads host() from a URI built from untrusted input and uses it for a security decision (an allow or deny list, an SSRF filter, deduplication, a cache key) sees the non-standard label, while a client that fetches the same URL resolves the NFC form, so the check and the fetch can disagree about the host."}], "id": "CVE-2026-19953", "lastModified": "2026-08-31T18:17:14.320", "metrics": {}, "published": "2026-08-31T18:17:14.320", "references": [{"source": "9b29abf9-4ab0-4765-b253-1875cd9b441e", "url": "https://github.com/libwww-perl/URI/commit/956619a9e94f86d8d2c529b4e06a3674c54a73e7.patch"}, {"source": "9b29abf9-4ab0-4765-b253-1875cd9b441e", "url": "https://github.com/libwww-perl/URI/pull/191"}, {"source": "9b29abf9-4ab0-4765-b253-1875cd9b441e", "url": "https://metacpan.org/release/OALDERS/URI-5.36/changes"}, {"source": "9b29abf9-4ab0-4765-b253-1875cd9b441e", "url": "https://www.rfc-editor.org/rfc/rfc5891#section-5.2"}], "sourceIdentifier": "9b29abf9-4ab0-4765-b253-1875cd9b441e", "vulnStatus": "Received", "weaknesses": [{"description": [{"lang": "en", "value": "CWE-1289"}], "source": "9b29abf9-4ab0-4765-b253-1875cd9b441e", "type": "Secondary"}]}

{}

{"created": "2026-08-31T18:30:03.947587+00:00", "updated": "2026-08-31T18:30:03.947600+00:00", "vendors": []}