MojoX::Authentication versions before 0.006 for Perl allow SAML authentication bypass because parse_assertion builds Net::SAML2::Binding::POST without a trust anchor.

parse_assertion in MojoX::Authentication::Model::SAML2 calls Net::SAML2::Binding::POST->new with no cacert, cert_text or anchors argument, then passes the returned XML to Net::SAML2::Protocol::Assertion->new_from_xml 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.
Advisories

No advisories yet.

Fixes

Solution

Upgrade to MojoX-Authentication 0.006 or later.


Workaround

For deployments that cannot upgrade, install Net::SAML2 0.86 or later. SAML login then fails rather than accepting a forged assertion.

History

Mon, 07 Sep 2026 08:45:00 +0000

Type Values Removed Values Added
First Time appeared Perl
Perl mojox::authentication
Vendors & Products Perl
Perl mojox::authentication

Sun, 06 Sep 2026 22:30:00 +0000

Type Values Removed Values Added
Description MojoX::Authentication versions before 0.006 for Perl allow SAML authentication bypass because parse_assertion builds Net::SAML2::Binding::POST without a trust anchor. parse_assertion in MojoX::Authentication::Model::SAML2 calls Net::SAML2::Binding::POST->new with no cacert, cert_text or anchors argument, then passes the returned XML to Net::SAML2::Protocol::Assertion->new_from_xml 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.
Title MojoX::Authentication versions before 0.006 for Perl allow SAML authentication bypass because parse_assertion builds Net::SAML2::Binding::POST without a trust anchor
Weaknesses CWE-347
References

Projects

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cve-icon MITRE

Status: PUBLISHED

Assigner: CPANSec

Published:

Updated: 2026-09-06T22:24:19.368Z

Reserved: 2026-09-06T17:59:12.036Z

Link: CVE-2026-86304

cve-icon Vulnrichment

No data.

cve-icon NVD

Status : Received

Published: 2026-09-06T23:17:39.483

Modified: 2026-09-06T23:17:39.483

Link: CVE-2026-86304

cve-icon Redhat

No data.

cve-icon OpenCVE Enrichment

Updated: 2026-09-07T08:24:28Z

Weaknesses