{"dataType":"CVE_RECORD","dataVersion":"5.2","cveMetadata":{"cveId":"CVE-2026-18089","assignerOrgId":"9b29abf9-4ab0-4765-b253-1875cd9b441e","state":"PUBLISHED","assignerShortName":"CPANSec","dateReserved":"2026-07-28T16:26:10.967Z","datePublished":"2026-08-03T12:42:08.879Z","dateUpdated":"2026-08-03T19:56:33.033Z"},"containers":{"cna":{"affected":[{"collectionURL":"https://cpan.org/modules","defaultStatus":"unaffected","packageName":"Net-SAML2","product":"Net::SAML2","programFiles":["lib/Net/SAML2/Role/VerifyXML.pm","lib/Net/SAML2/Binding/POST.pm","lib/Net/SAML2/Protocol/Assertion.pm"],"programRoutines":[{"name":"Net::SAML2::Role::VerifyXML::verify_xml"},{"name":"Net::SAML2::Binding::POST::handle_response"},{"name":"Net::SAML2::Protocol::Assertion::_verify_encrypted_assertion"}],"repo":"https://github.com/perl-net-saml2/perl-Net-SAML2","vendor":"TIMLEGGE","versions":[{"lessThan":"0.86","status":"affected","version":"0","versionType":"custom"}]}],"descriptions":[{"lang":"en","value":"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->new_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."}],"impacts":[{"capecId":"CAPEC-115","descriptions":[{"lang":"en","value":"CAPEC-115 Authentication Bypass"}]}],"problemTypes":[{"descriptions":[{"cweId":"CWE-347","description":"CWE-347 Improper Verification of Cryptographic Signature","lang":"en","type":"CWE"}]},{"descriptions":[{"cweId":"CWE-295","description":"CWE-295 Improper Certificate Validation","lang":"en","type":"CWE"}]}],"providerMetadata":{"orgId":"9b29abf9-4ab0-4765-b253-1875cd9b441e","shortName":"CPANSec","dateUpdated":"2026-08-03T12:42:08.879Z"},"references":[{"tags":["release-notes"],"url":"https://metacpan.org/release/TIMLEGGE/Net-SAML2-0.88/source/Changes"},{"url":"https://metacpan.org/release/TIMLEGGE/Net-SAML2-0.85/source/lib/Net/SAML2/Role/VerifyXML.pm#L32"},{"url":"https://metacpan.org/release/TIMLEGGE/Net-SAML2-0.85/source/lib/Net/SAML2/Binding/POST.pm#L21"},{"url":"https://metacpan.org/release/TIMLEGGE/Net-SAML2-0.85/source/lib/Net/SAML2/Protocol/Assertion.pm#L84"}],"solutions":[{"lang":"en","value":"Upgrade to Net::SAML2 0.86 or later, which requires a cacert or cert_text trust anchor before a response or assertion signature is verified."}],"source":{"discovery":"UNKNOWN"},"timeline":[{"lang":"en","time":"2026-07-31T00:00:00.000Z","value":"Version 0.86 released with fix."},{"lang":"en","time":"2026-07-31T00:00:00.000Z","value":"Version 0.88 released, re-issuing 0.86 with a corrected version number."}],"title":"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","workarounds":[{"lang":"en","value":"For deployments that cannot upgrade, construct Net::SAML2::Binding::POST, and call Net::SAML2::Protocol::Assertion->new_from_xml, with a cacert, cert_text, or anchors argument identifying the IdP signing certificate."}],"x_generator":{"engine":"cpansec-cna-tool 0.1"}},"adp":[{"metrics":[{"cvssV3_1":{"scope":"UNCHANGED","version":"3.1","baseScore":7.5,"attackVector":"NETWORK","baseSeverity":"HIGH","vectorString":"CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:N/I:H/A:N","integrityImpact":"HIGH","userInteraction":"NONE","attackComplexity":"LOW","availabilityImpact":"NONE","privilegesRequired":"NONE","confidentialityImpact":"NONE"}},{"other":{"type":"ssvc","content":{"timestamp":"2026-08-03T19:56:09.872860Z","id":"CVE-2026-18089","options":[{"Exploitation":"none"},{"Automatable":"yes"},{"Technical Impact":"partial"}],"role":"CISA Coordinator","version":"2.0.3"}}}],"title":"CISA ADP Vulnrichment","providerMetadata":{"orgId":"134c704f-9b21-4f2e-91b3-4a467353bcc0","shortName":"CISA-ADP","dateUpdated":"2026-08-03T19:56:33.033Z"}}]}}