CVE-2026-86304: MojoX::Authentication versions before 0.006 for Perl allow SAML authentication bypass because parse_assertion builds Net::SAML2::Binding::POST without a trust anchor
MojoX::Authentication versions before 0.006 for Perl allow SAML authentication bypass because parseassertion builds Net::SAML2::Binding::POST without a trust anchor.
parseassertion in MojoX::Authentication::Model::SAML2 calls Net::SAML2::Binding::POST->new with no cacert, certtext or anchors argument, then passes the returned XML to Net::SAML2::Protocol::Assertion->newfromxml with the IdP signing certificate as cacert. In Net::SAML2 before 0.86 that certificate guards only encrypted assertions, so the signature on an unencrypted assertion is checked against the certificate the response itself carries.
An attacker starts a SAML login, then posts a response signed with a certificate of their own. The audience, InResponseTo and timestamp checks that follow are all satisfiable by the attacker, so the response authenticates any NameID it carries.
Affected Software
Remediation
Recommended actions to resolve this vulnerability, in priority order.
- Upgrade
Upgrade
MojoX::Authenticationto a version that resolves this vulnerability.Fixed in 0.006Patch MojoX-Authentication 0.006 or later
Event History
Frequently Asked Questions
Which deployments are affected?
Deployments using MojoX::Authentication versions earlier than 0.006 with its SAML2 authentication model are affected. The described validation behavior also depends on Net::SAML2 before 0.86, where the IdP signing certificate does not protect signatures on unencrypted assertions.
What does an attacker need to do to exploit this?
An attacker must be able to initiate a SAML login and submit a crafted SAML response. They can sign an unencrypted assertion with their own certificate and choose the NameID to be authenticated, while satisfying the audience, InResponseTo, and timestamp checks.
How can I determine whether my application is exposed?
Check whether the application uses MojoX::Authentication earlier than 0.006 and the MojoX::Authentication::Model::SAML2 SAML flow. Also determine whether the installed Net::SAML2 version is earlier than 0.86, because that version range accepts the response-provided certificate for unencrypted assertion signature validation.