{"id":"CVE-2026-18089","summary":"Net::SAML2 versions before 0.86 for Perl allow SAML authentication bypass by verifying responses against the response-embedded certificate in verify_xml when no trust anchor is configured","details":"Net::SAML2 versions before 0.86 for Perl allow SAML authentication bypass by verifying responses against the response-embedded certificate in verify_xml when no trust anchor is configured.\n\nverify_xml in Net::SAML2::Role::VerifyXML runs \"return if !$anchors && !$cacert;\" as soon as the XML::Sig check succeeds, and that check uses the X.509 certificate taken from the response's own dsig:KeyInfo/dsig:X509Certificate element, so an unanchored response is checked only against the key it carries. Binding::POST declares cacert as an optional Maybe[Str] with no default, so a POST binding built without one takes that path, and _verify_encrypted_assertion returns early the same way with \"return $xml unless $cacert;\".\n\nAny caller that constructs Binding::POST or calls Assertion-\u003enew_from_xml without a cacert, cert_text, or anchors argument accepts a response signed by an attacker generated key whose self-signed certificate is embedded in that response, authenticating an arbitrary assertion.","modified":"2026-08-12T04:17:26.134883895Z","published":"2026-08-03T12:42:08.879Z","database_specific":{"cna_assigner":"CPANSec","cwe_ids":["CWE-295","CWE-347"],"osv_generated_from":"https://github.com/CVEProject/cvelistV5/tree/main/cves/2026/18xxx/CVE-2026-18089.json"},"references":[{"type":"WEB","url":"https://cpan.org/modules"},{"type":"WEB","url":"https://metacpan.org/release/TIMLEGGE/Net-SAML2-0.85/source/lib/Net/SAML2/Binding/POST.pm#L21"},{"type":"WEB","url":"https://metacpan.org/release/TIMLEGGE/Net-SAML2-0.85/source/lib/Net/SAML2/Protocol/Assertion.pm#L84"},{"type":"WEB","url":"https://metacpan.org/release/TIMLEGGE/Net-SAML2-0.85/source/lib/Net/SAML2/Role/VerifyXML.pm#L32"},{"type":"ADVISORY","url":"https://github.com/CVEProject/cvelistV5/tree/main/cves/2026/18xxx/CVE-2026-18089.json"},{"type":"ADVISORY","url":"https://metacpan.org/release/TIMLEGGE/Net-SAML2-0.88/source/Changes"},{"type":"ADVISORY","url":"https://nvd.nist.gov/vuln/detail/CVE-2026-18089"},{"type":"PACKAGE","url":"https://github.com/perl-net-saml2/perl-Net-SAML2"}],"affected":[{"ranges":[{"type":"GIT","repo":"https://github.com/perl-net-saml2/perl-net-saml2","events":[{"introduced":"0"},{"fixed":"b679659178e278a4a53fe88d9eb58461a6e78b13"}],"database_specific":{"source":"AFFECTED_FIELD","extracted_events":[{"introduced":"0"},{"fixed":"0.86"}]}}],"versions":["0.85","0.84","0.83","0.82","0.81","0.80","0.79","0.78","0.77","0.76","0.75","0.74","0.73","0.72","0.71","0.70","0.69","0.68","0.67","0.66","0.65","0.64","0.63","0.62","0.61","0.60","0.58","0.57","0.56","0.55","0.54","0.53","0.52","0.51","0.49","0.48","0.47","0.45","0.44","0.43","0.42","0.41","0.40","0.39","0.38","0.37-TRIAL","0.36-TRIAL","0.35-TRIAL","0.34","0.33-TRIAL","0.32","0.31-TRIAL","0.30-TRIAL","0.29","v0.26-TRIAL","0.25","v0.20","0.20","0.20.03-TRIAL","perl-net-saml2-0.19.05","0.19.05","v0.17_06","v0.17","v0.16","v0.15","v0.14","v0.12","v0.11","v0.10"],"database_specific":{"source":"https://storage.googleapis.com/cve-osv-conversion/osv-output/CVE-2026-18089.json"}}],"schema_version":"1.9.0","severity":[{"type":"CVSS_V3","score":"CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:N/I:H/A:N"}]}