Vulnerability-Lookup

CVE-2026-18092 (GCVE-0-2026-18092)

Vulnerability from cvelistv5 – Published: 2026-08-03 13:24 – Updated: 2026-08-03 20:01

Title

Summary

Net::SAML2 versions before 0.86 for Perl allow SAML authentication bypass via XML signature wrapping because new_from_xml reads assertion identity with document-wide XPath instead of the signed subtree. new_from_xml reads the NameID, attribute values, SessionIndex, audience and other identity fields with document-wide XPath, such as //saml:Assertion/saml:AttributeStatement/saml:Attribute and //saml:Subject/saml:NameID, which select the first matching element in document order rather than the element covered by the verified signature. handle_response confirms that a signature is present and, when a cacert is configured, that it chains to the CA, but XML::Sig verifies only the element named by the signature's Reference URI, so unsigned sibling assertions in the same document are not covered. An attacker who holds any one IdP-signed assertion can add an unsigned attacker-authored assertion earlier in document order; the signature still verifies and the document-order XPath returns the attacker's NameID and attributes. Any caller that passes an untrusted Response to new_from_xml can accept identity fields from an assertion the IdP never signed, even when a cacert trust anchor is configured, so a party holding one valid IdP-signed assertion can authenticate as an arbitrary user.

Severity

8.1 (High)


                        
                          CVSS:3.1/AV:N/AC:L/PR:N/UI:R/S:U/C:N/I:H/A:H

SSVC

Exploitation: none Automatable: no Technical Impact: partial

CISA Coordinator · CISA-ADP (v2.0.3)

Decision recorded 2026-08-03 20:00 UTC

CWE

CWE-347 - Improper Verification of Cryptographic Signature

Assigner

CPANSec CNA under the redhat root

CNA scorecard C 62/100 over 369 records in the last 180 days details

References

2 references

URL	Tags
https://metacpan.org/release/TIMLEGGE/Net-SAML2-0…	release-notes
https://github.com/perl-net-saml2/perl-Net-SAML2/…	patch

Impacted products

1 product

Vendor	Product	Version	CPE status
TIMLEGGE	Net::SAML2	Affected: 0 , < 0.86 (custom)	guessed

Show details on NVD website

JSON

To clipboard

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FKIE_CVE-2026-18092

Vulnerability from fkie_nvd - Published: 2026-08-03 14:16 - Updated: 2026-10-23 21:10

Severity

8.1 (High) - CVSS:3.1/AV:N/AC:L/PR:N/UI:R/S:U/C:N/I:H/A:H

Summary

References

	URL	Tags
	9b29abf9-4ab0-4765-b253-1875cd9b441e	https://github.com/perl-net-saml2/perl-Net-SAML2/commit/201fead7f42b83f40c84bf4a311a25b09acd18f9.patch	Patch
	9b29abf9-4ab0-4765-b253-1875cd9b441e	https://metacpan.org/release/TIMLEGGE/Net-SAML2-0.86/changes	Release Notes

Impacted products

	Vendor	Product	Version
	timlegge	net\	\

JSON

To clipboard

{
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    {
      "lang": "es",
      "value": "Las versiones de Net::SAML2 anteriores a la 0.86 para Perl permiten la omisi\u00f3n de autenticaci\u00f3n SAML mediante la envoltura de firma XML porque new_from_xml lee la identidad de la aserci\u00f3n con XPath a nivel de documento en lugar del sub\u00e1rbol firmado.\n\nnew_from_xml lee el NameID, los valores de atributos, SessionIndex, la audiencia y otros campos de identidad con XPath a nivel de documento, como //saml:Assertion/saml:AttributeStatement/saml:Attribute y //saml:Subject/saml:NameID, que seleccionan el primer elemento coincidente en el orden del documento en lugar del elemento cubierto por la firma verificada. handle_response confirma que una firma est\u00e1 presente y, cuando se configura un cacert, que encadena a la CA, pero XML::Sig verifica solo el elemento nombrado por la URI de referencia de la firma, por lo que las aserciones hermanas sin firmar en el mismo documento no est\u00e1n cubiertas. Un atacante que posee cualquier aserci\u00f3n firmada por el IdP puede a\u00f1adir una aserci\u00f3n sin firmar, creada por el atacante, antes en el orden del documento; la firma a\u00fan se verifica y el XPath en orden de documento devuelve el NameID y los atributos del atacante.\n\nCualquier llamador que pasa una Respuesta no confiable a new_from_xml puede aceptar campos de identidad de una aserci\u00f3n que el IdP nunca firm\u00f3, incluso cuando se configura un ancla de confianza cacert, por lo que una parte que posee una aserci\u00f3n v\u00e1lida firmada por el IdP puede autenticarse como un usuario arbitrario."
    }
  ],
  "id": "CVE-2026-18092",
  "lastModified": "2026-10-23T21:10:00.157",
  "metrics": {
    "cvssMetricV31": [
      {
        "cvssData": {
          "attackComplexity": "LOW",
          "attackVector": "NETWORK",
          "availabilityImpact": "HIGH",
          "baseScore": 8.1,
          "baseSeverity": "HIGH",
          "confidentialityImpact": "NONE",
          "integrityImpact": "HIGH",
          "privilegesRequired": "NONE",
          "scope": "UNCHANGED",
          "userInteraction": "REQUIRED",
          "vectorString": "CVSS:3.1/AV:N/AC:L/PR:N/UI:R/S:U/C:N/I:H/A:H",
          "version": "3.1"
        },
        "exploitabilityScore": 2.8,
        "impactScore": 5.2,
        "source": "134c704f-9b21-4f2e-91b3-4a467353bcc0",
        "type": "Secondary"
      }
    ],
    "ssvcV203": [
      {
        "source": "134c704f-9b21-4f2e-91b3-4a467353bcc0",
        "ssvcData": {
          "id": "CVE-2026-18092",
          "options": [
            {
              "exploitation": "none"
            },
            {
              "automatable": "no"
            },
            {
              "technicalImpact": "partial"
            }
          ],
          "role": "CISA Coordinator",
          "timestamp": "2026-08-03T20:00:23.033425Z",
          "version": "2.0.3"
        }
      }
    ]
  },
  "published": "2026-08-03T14:16:25.030",
  "references": [
    {
      "source": "9b29abf9-4ab0-4765-b253-1875cd9b441e",
      "tags": [
        "Patch"
      ],
      "url": "https://github.com/perl-net-saml2/perl-Net-SAML2/commit/201fead7f42b83f40c84bf4a311a25b09acd18f9.patch"
    },
    {
      "source": "9b29abf9-4ab0-4765-b253-1875cd9b441e",
      "tags": [
        "Release Notes"
      ],
      "url": "https://metacpan.org/release/TIMLEGGE/Net-SAML2-0.86/changes"
    }
  ],
  "sourceIdentifier": "9b29abf9-4ab0-4765-b253-1875cd9b441e",
  "vulnStatus": "Analyzed",
  "weaknesses": [
    {
      "description": [
        {
          "lang": "en",
          "value": "CWE-347"
        }
      ],
      "source": "9b29abf9-4ab0-4765-b253-1875cd9b441e",
      "type": "Secondary"
    }
  ]
}

GHSA-657V-XPF8-79X2

Vulnerability from github – Published: 2026-08-03 15:32 – Updated: 2026-08-03 21:31

Details

new_from_xml reads the NameID, attribute values, SessionIndex, audience and other identity fields with document-wide XPath, such as //saml:Assertion/saml:AttributeStatement/saml:Attribute and //saml:Subject/saml:NameID, which select the first matching element in document order rather than the element covered by the verified signature. handle_response confirms that a signature is present and, when a cacert is configured, that it chains to the CA, but XML::Sig verifies only the element named by the signature's Reference URI, so unsigned sibling assertions in the same document are not covered. An attacker who holds any one IdP-signed assertion can add an unsigned attacker-authored assertion earlier in document order; the signature still verifies and the document-order XPath returns the attacker's NameID and attributes.

Any caller that passes an untrusted Response to new_from_xml can accept identity fields from an assertion the IdP never signed, even when a cacert trust anchor is configured, so a party holding one valid IdP-signed assertion can authenticate as an arbitrary user.

Severity

8.1 (High)


                  
                    CVSS:3.1/AV:N/AC:L/PR:N/UI:R/S:U/C:N/I:H/A:H

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{
  "affected": [],
  "aliases": [
    "CVE-2026-18092"
  ],
  "database_specific": {
    "cwe_ids": [
      "CWE-347"
    ],
    "github_reviewed": false,
    "github_reviewed_at": null,
    "nvd_published_at": "2026-08-03T14:16:25Z",
    "severity": "HIGH"
  },
  "details": "Net::SAML2 versions before 0.86 for Perl allow SAML authentication bypass via XML signature wrapping because new_from_xml reads assertion identity with document-wide XPath instead of the signed subtree.\n\nnew_from_xml reads the NameID, attribute values, SessionIndex, audience and other identity fields with document-wide XPath, such as //saml:Assertion/saml:AttributeStatement/saml:Attribute and //saml:Subject/saml:NameID, which select the first matching element in document order rather than the element covered by the verified signature. handle_response confirms that a signature is present and, when a cacert is configured, that it chains to the CA, but XML::Sig verifies only the element named by the signature\u0027s Reference URI, so unsigned sibling assertions in the same document are not covered. An attacker who holds any one IdP-signed assertion can add an unsigned attacker-authored assertion earlier in document order; the signature still verifies and the document-order XPath returns the attacker\u0027s NameID and attributes.\n\nAny caller that passes an untrusted Response to new_from_xml can accept identity fields from an assertion the IdP never signed, even when a cacert trust anchor is configured, so a party holding one valid IdP-signed assertion can authenticate as an arbitrary user.",
  "id": "GHSA-657v-xpf8-79x2",
  "modified": "2026-08-03T21:31:35Z",
  "published": "2026-08-03T15:32:47Z",
  "references": [
    {
      "type": "ADVISORY",
      "url": "https://nvd.nist.gov/vuln/detail/CVE-2026-18092"
    },
    {
      "type": "WEB",
      "url": "https://github.com/perl-net-saml2/perl-Net-SAML2/commit/201fead7f42b83f40c84bf4a311a25b09acd18f9.patch"
    },
    {
      "type": "WEB",
      "url": "https://metacpan.org/release/TIMLEGGE/Net-SAML2-0.86/changes"
    }
  ],
  "schema_version": "1.4.0",
  "severity": [
    {
      "score": "CVSS:3.1/AV:N/AC:L/PR:N/UI:R/S:U/C:N/I:H/A:H",
      "type": "CVSS_V3"
    }
  ]
}

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Not confirmed: The user expressed doubt about the validity of the vulnerability.
Not patched: The vulnerability was not observed as successfully patched by the user who reported the sighting.

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The MITRE ATT&CK techniques below are AI-generated suggestions, inferred from the description of the vulnerability by the CIRCL/vulnerability-attack-technique-classification-roberta-base model, served locally by ML-Gateway. They have not been verified by an analyst and are provided for guidance only.
The approach is described in our paper Mapping CVEs to MITRE ATT&CK Techniques: A Curated Gold-Set Classifier and the Limits of LLM-Assisted Label Expansion.
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CVE-2026-18092 (GCVE-0-2026-18092)

FKIE_CVE-2026-18092

GHSA-657V-XPF8-79X2

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