[CVE-2026-18089] Net::SAML2 versions before 0.86 for Perl allow SAML authentication bypass by verifying responses aga…

Descripción técnica

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. verify_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;". Any 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.

Puntuación CVSS

Score: 7.5/10 — Severidad: HIGH — Estado NIST: Awaiting Analysis

CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:N/I:H/A:N

Debilidades (CWE)

CWE-295, CWE-347

Fuente oficial

Publicado en NIST NVD.