{"id":"CVE-2026-18092","summary":"Net::SAML2 versions before 0.86 for Perl allow SAML authentication bypass via XML signature wrapping because new_from_xml reads assertion identity with document-wide XPath instead of the signed subtree","details":"Net::SAML2 versions before 0.86 for Perl allow SAML authentication bypass via XML signature wrapping because new_from_xml reads assertion identity with document-wide XPath instead of the signed subtree.\n\nnew_from_xml reads the NameID, attribute values, SessionIndex, audience and other identity fields with document-wide XPath, such as //saml:Assertion/saml:AttributeStatement/saml:Attribute and //saml:Subject/saml:NameID, which select the first matching element in document order rather than the element covered by the verified signature. handle_response confirms that a signature is present and, when a cacert is configured, that it chains to the CA, but XML::Sig verifies only the element named by the signature's Reference URI, so unsigned sibling assertions in the same document are not covered. An attacker who holds any one IdP-signed assertion can add an unsigned attacker-authored assertion earlier in document order; the signature still verifies and the document-order XPath returns the attacker's NameID and attributes.\n\nAny caller that passes an untrusted Response to new_from_xml can accept identity fields from an assertion the IdP never signed, even when a cacert trust anchor is configured, so a party holding one valid IdP-signed assertion can authenticate as an arbitrary user.","modified":"2026-08-08T03:30:15.588064060Z","published":"2026-08-03T13:24:52.137Z","database_specific":{"osv_generated_from":"https://github.com/CVEProject/cvelistV5/tree/main/cves/2026/18xxx/CVE-2026-18092.json","unresolved_ranges":[{"source":"AFFECTED_FIELD","extracted_events":[{"fixed":"0.86"}]},{"source":"DESCRIPTION","extracted_events":[{"fixed":"0.86"}]}],"cna_assigner":"CPANSec","cwe_ids":["CWE-347"]},"references":[{"type":"WEB","url":"https://cpan.org/modules"},{"type":"ADVISORY","url":"https://github.com/CVEProject/cvelistV5/tree/main/cves/2026/18xxx/CVE-2026-18092.json"},{"type":"ADVISORY","url":"https://metacpan.org/release/TIMLEGGE/Net-SAML2-0.86/changes"},{"type":"ADVISORY","url":"https://nvd.nist.gov/vuln/detail/CVE-2026-18092"},{"type":"FIX","url":"https://github.com/perl-net-saml2/perl-Net-SAML2/commit/201fead7f42b83f40c84bf4a311a25b09acd18f9.patch"},{"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":"201fead7f42b83f40c84bf4a311a25b09acd18f9"}],"database_specific":{"source":"REFERENCES"}}],"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-2026-18092.json"}}],"schema_version":"1.8.0","severity":[{"type":"CVSS_V3","score":"CVSS:3.1/AV:N/AC:L/PR:N/UI:R/S:U/C:N/I:H/A:H"}]}