CVE-2026-19953

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{"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": "2026-09-03T16:41:09.297", "metrics": {"cvssMetricV31": [{"cvssData": {"attackComplexity": "LOW", "attackVector": "NETWORK", "availabilityImpact": "NONE", "baseScore": 6.5, "baseSeverity": "MEDIUM", "confidentialityImpact": "LOW", "integrityImpact": "LOW", "privilegesRequired": "NONE", "scope": "UNCHANGED", "userInteraction": "NONE", "vectorString": "CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:L/I:L/A:N", "version": "3.1"}, "exploitabilityScore": 3.9, "impactScore": 2.5, "source": "134c704f-9b21-4f2e-91b3-4a467353bcc0", "type": "Secondary"}], "ssvcV203": [{"source": "134c704f-9b21-4f2e-91b3-4a467353bcc0", "ssvcData": {"id": "CVE-2026-19953", "options": [{"exploitation": "none"}, {"automatable": "yes"}, {"technicalImpact": "partial"}], "role": "CISA Coordinator", "timestamp": "2026-09-01T15:16:46.820304Z", "version": "2.0.3"}}]}, "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"}, {"source": "af854a3a-2127-422b-91ae-364da2661108", "url": "http://www.openwall.com/lists/oss-security/2026/08/31/14"}], "sourceIdentifier": "9b29abf9-4ab0-4765-b253-1875cd9b441e", "vulnStatus": "Deferred", "weaknesses": [{"description": [{"lang": "en", "value": "CWE-1289"}], "source": "9b29abf9-4ab0-4765-b253-1875cd9b441e", "type": "Secondary"}]}

{}

{"affected": [{"configurations": [{"platform": null, "status": "affected", "versions": {"scheme": "generic", "value": "[0,5.36)"}}], "enrichment": {"confidence": 80.0, "confidence_source": "inferred", "scores": [{"score": 80.0, "source": "inferred"}]}, "product": "uri", "vendor": "libwww-perl"}], "created": "2026-08-31T18:30:03.947587+00:00", "updated": "2026-09-02T00:00:06.752753+00:00", "vendors": ["libwww-perl", "libwww-perl$PRODUCT$uri"]}