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CVE-2026-86304 CPAN Security Group
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CVE ID: CVE-2026-86304
Distribution: MojoX-Authentication
Versions: before 0.006
MetaCPAN: https://metacpan.org/dist/MojoX-Authentication
MojoX::Authentication versions before 0.006 for Perl allow SAML
authentication bypass because parse_assertion builds
Net::SAML2::Binding::POST without a trust anchor
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.
Problem types
-------------
- CWE-347 Improper Verification of Cryptographic Signature
Impacts
-------
- CAPEC-115 Authentication Bypass
Workarounds
-----------
For deployments that cannot upgrade, install Net::SAML2 0.86 or later.
SAML login then fails rather than accepting a forged assertion.
Solutions
---------
Upgrade to MojoX-Authentication 0.006 or later.
References
----------
https://metacpan.org/release/POLETTIX/MojoX-Authentication-0.006/source/Changes
https://metacpan.org/release/POLETTIX/MojoX-Authentication-0.004/source/lib/MojoX/Authentication/Model/SAML2.pm#L188
https://www.cve.org/CVERecord?id=CVE-2026-18089
Timeline
--------
- 2026-07-31: Version 0.006 released with fix.
