PT-2026-67393 · Timlegge · Net::Saml2
CVE-2026-18089
·
Published
2026-08-03
·
Updated
2026-08-03
CVSS v3.1
7.5
High
| Vector | AV:N/AC:L/PR:N/UI:N/S:U/C:N/I:H/A:N |
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.
Fix
Improper Certificate Validation
Improper Verification of Cryptographic Signature
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Related Identifiers
Affected Products
Net::Saml2