{"id":"CVE-2026-18092","aliases":["EUVD-2026-52291","GHSA-657v-xpf8-79x2"],"status":"published","title":"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","description":"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.","severity":{"version":"3.1","score":8.1,"vector":"CVSS:3.1/AV:N/AC:L/PR:N/UI:R/S:U/C:N/I:H/A:H","level":"high","assessor":"adp","from":"cve"},"epss":{"day":"2026-11-09","score":0.00337,"percentile":0.27321,"model":"v2026.06.15"},"facts":{"in_kev":false,"known_exploited":false,"public_exploit":false,"fix_available":false},"cwes":["CWE-347"],"published":"2026-08-03T13:24:52Z","modified":"2026-10-28T02:30:54Z","products":[{"vendor":"timlegge","product":"net::saml2"},{"vendor":"timlegge","product":"net\\"}],"references":[{"url":"https://metacpan.org/release/TIMLEGGE/Net-SAML2-0.86/changes","tags":["release-notes","Release Notes","advisory"]},{"url":"https://github.com/perl-net-saml2/perl-Net-SAML2/commit/201fead7f42b83f40c84bf4a311a25b09acd18f9.patch","tags":["patch","Patch","fix"]},{"url":"https://nvd.nist.gov/vuln/detail/CVE-2026-18092","tags":["advisory"]},{"url":"https://github.com/advisories/GHSA-657v-xpf8-79x2"},{"url":"https://cpan.org/modules","tags":["web"]},{"url":"https://github.com/CVEProject/cvelistV5/tree/main/cves/2026/18xxx/CVE-2026-18092.json","tags":["advisory"]},{"url":"https://github.com/perl-net-saml2/perl-Net-SAML2","tags":["package"]}],"sources":{"cve":[{"id":"CVE-2026-18092","title":"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","description":"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.","status":"published","published":"2026-08-03T13:24:52.137Z","modified":"2026-08-03T20:01:20.742Z","cvss":[{"version":"3.1","score":8.1,"vector":"CVSS:3.1/AV:N/AC:L/PR:N/UI:R/S:U/C:N/I:H/A:H","level":"high","assessor":"adp"}],"cwes":["CWE-347"],"updated_at":"2026-11-02T14:20:12.60856Z"}],"euvd":[{"id":"EUVD-2026-52291","description":"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.","status":"published","published":"2026-08-03T13:24:52Z","modified":"2026-08-03T20:01:20Z","cvss":[{"version":"3.1","score":8.1,"vector":"CVSS:3.1/AV:N/AC:L/PR:N/UI:R/S:U/C:N/I:H/A:H","level":"high"}],"updated_at":"2026-11-02T18:02:23.68186Z"}],"ghsa":[{"id":"GHSA-657v-xpf8-79x2","title":"Net::SAML2 versions before 0.86 for Perl allow SAML authentication bypass via XML signature...","description":"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.","status":"published","published":"2026-08-03T15:32:47Z","modified":"2026-08-03T21:31:35Z","cvss":[{"version":"3.1","score":8.1,"vector":"CVSS:3.1/AV:N/AC:L/PR:N/UI:R/S:U/C:N/I:H/A:H","level":"high"}],"cwes":["CWE-347"],"updated_at":"2026-11-02T15:10:02.88062Z"}],"nvd":[{"id":"CVE-2026-18092","description":"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.","status":"published","published":"2026-08-03T14:16:25.03Z","modified":"2026-10-23T21:10:00.157Z","cvss":[{"version":"3.1","score":8.1,"vector":"CVSS:3.1/AV:N/AC:L/PR:N/UI:R/S:U/C:N/I:H/A:H","level":"high","assessor":"secondary"}],"cwes":["CWE-347"],"updated_at":"2026-11-02T14:12:34.643497Z"}],"osv":[{"id":"CVE-2026-18092","title":"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","description":"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.","status":"published","published":"2026-08-03T13:24:52.137Z","modified":"2026-10-28T02:30:54.441329582Z","cvss":[{"version":"3.1","score":8.1,"vector":"CVSS:3.1/AV:N/AC:L/PR:N/UI:R/S:U/C:N/I:H/A:H","level":"high"}],"cwes":["CWE-347"],"updated_at":"2026-11-02T15:44:58.024074Z"}]}}