{"id":"CVE-2026-18092","url":"https://www.cyber-defence.io/tools/cve/CVE-2026-18092","generatedAt":"2026-10-28T03:23:52.362Z","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. new_from_xml reads the NameID, attribute values,…","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.","published":"2026-08-03T14:16:25.000Z","lastModified":"2026-10-23T21:10:00.000Z","status":"Analyzed","sourceIdentifier":"9b29abf9-4ab0-4765-b253-1875cd9b441e","cvss":{"version":"3.1","score":8.1,"severity":"HIGH","vector":"CVSS:3.1/AV:N/AC:L/PR:N/UI:R/S:U/C:N/I:H/A:H"},"cwe":["CWE-347"],"affected":["timlegge/net\\"],"epss":{"score":0.00337,"percentile":0.26918,"date":"2026-10-26","history":[]},"kev":{"listed":false},"exploits":{"count":0,"verified":false,"firstPublished":null,"source":"Exploit-DB (https://gitlab.com/exploit-database/exploitdb)","entries":[]},"verdict":{"level":"high","text":"High impact if exploited, but EPSS currently rates exploitation as unlikely (0.34%). Schedule it in the normal patch cycle and watch for a rise in EPSS or a public exploit."},"changes":[],"references":[{"url":"https://github.com/perl-net-saml2/perl-Net-SAML2/commit/201fead7f42b83f40c84bf4a311a25b09acd18f9.patch","tags":["Patch"],"source":"9b29abf9-4ab0-4765-b253-1875cd9b441e"},{"url":"https://metacpan.org/release/TIMLEGGE/Net-SAML2-0.86/changes","tags":["Release Notes"],"source":"9b29abf9-4ab0-4765-b253-1875cd9b441e"}],"sources":{"nvd":"https://nvd.nist.gov/vuln/detail/CVE-2026-18092","epss":"https://www.first.org/epss/","kev":"https://www.cisa.gov/known-exploited-vulnerabilities-catalog","exploitdb":"https://www.exploit-db.com/"},"licence":"CC BY 4.0 — link back to the CVE Explorer if you publish the results; upstream data remains subject to its own terms."}