# CVE-2026-86304

## Summary

- **CVE ID:** CVE-2026-86304
- **Severity:** CRITICAL
- **CVSS Score:** 9.8 (CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:H/I:H/A:H)
- **CWE:** CWE-347
- **Published:** Sep 6, 2026
- **Last Modified:** Sep 8, 2026

## 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.

## Affected Products

- Unknown product (0)

## References

- [CNA](https://metacpan.org/release/POLETTIX/MojoX-Authentication-0.006/source/Changes)
- [CNA](https://metacpan.org/release/POLETTIX/MojoX-Authentication-0.004/source/lib/MojoX/Authentication/Model/SAML2.pm#L188)
- [CNA](https://www.cve.org/CVERecord?id=CVE-2026-18089)

## Exploitation Prediction (EPSS)

- **EPSS Score:** 0.22%
- **EPSS Percentile:** 13.2

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_Exported from OnDuty AI Vulnerability Intelligence on 2026-09-10._