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FKIE_CVE-2026-18089

Vulnerability from fkie_nvd - Published: 2026-08-03 14:16 - Updated: 2026-08-06 18:36
Severity
7.5 (High) - CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:N/I:H/A:N
Summary
Net::SAML2 versions before 0.86 for Perl allow SAML authentication bypass by verifying responses against the response-embedded certificate in verify_xml when no trust anchor is configured. verify_xml in Net::SAML2::Role::VerifyXML runs "return if !$anchors && !$cacert;" as soon as the XML::Sig check succeeds, and that check uses the X.509 certificate taken from the response's own dsig:KeyInfo/dsig:X509Certificate element, so an unanchored response is checked only against the key it carries. Binding::POST declares cacert as an optional Maybe[Str] with no default, so a POST binding built without one takes that path, and _verify_encrypted_assertion returns early the same way with "return $xml unless $cacert;". Any caller that constructs Binding::POST or calls Assertion->new_from_xml without a cacert, cert_text, or anchors argument accepts a response signed by an attacker generated key whose self-signed certificate is embedded in that response, authenticating an arbitrary assertion.
References
9b29abf9-4ab0-4765-b253-1875cd9b441ehttps://metacpan.org/release/TIMLEGGE/Net-SAML2-0.85/source/lib/Net/SAML2/Binding/POST.pm#L21Product
9b29abf9-4ab0-4765-b253-1875cd9b441ehttps://metacpan.org/release/TIMLEGGE/Net-SAML2-0.85/source/lib/Net/SAML2/Protocol/Assertion.pm#L84Product
9b29abf9-4ab0-4765-b253-1875cd9b441ehttps://metacpan.org/release/TIMLEGGE/Net-SAML2-0.85/source/lib/Net/SAML2/Role/VerifyXML.pm#L32Product
9b29abf9-4ab0-4765-b253-1875cd9b441ehttps://metacpan.org/release/TIMLEGGE/Net-SAML2-0.88/source/ChangesRelease Notes
Impacted products
Vendor Product Version
timlegge net\ \
To clipboard 

{
  "affected": [
    {
      "affectedData": [
        {
          "collectionURL": "https://cpan.org/modules",
          "defaultStatus": "unaffected",
          "packageName": "Net-SAML2",
          "product": "Net::SAML2",
          "programFiles": [
            "lib/Net/SAML2/Role/VerifyXML.pm",
            "lib/Net/SAML2/Binding/POST.pm",
            "lib/Net/SAML2/Protocol/Assertion.pm"
          ],
          "programRoutines": [
            {
              "name": "Net::SAML2::Role::VerifyXML::verify_xml"
            },
            {
              "name": "Net::SAML2::Binding::POST::handle_response"
            },
            {
              "name": "Net::SAML2::Protocol::Assertion::_verify_encrypted_assertion"
            }
          ],
          "repo": "https://github.com/perl-net-saml2/perl-Net-SAML2",
          "vendor": "TIMLEGGE",
          "versions": [
            {
              "lessThan": "0.86",
              "status": "affected",
              "version": "0",
              "versionType": "custom"
            }
          ]
        }
      ],
      "source": "9b29abf9-4ab0-4765-b253-1875cd9b441e"
    }
  ],
  "configurations": [
    {
      "nodes": [
        {
          "cpeMatch": [
            {
              "criteria": "cpe:2.3:a:timlegge:net\\:\\:saml2:*:*:*:*:*:perl:*:*",
              "matchCriteriaId": "69FF1709-62F7-4E8C-B90D-ABFA96B07FF1",
              "versionEndExcluding": "0.86",
              "vulnerable": true
            }
          ],
          "negate": false,
          "operator": "OR"
        }
      ]
    }
  ],
  "cveTags": [],
  "descriptions": [
    {
      "lang": "en",
      "value": "Net::SAML2 versions before 0.86 for Perl allow SAML authentication bypass by verifying responses against the response-embedded certificate in verify_xml when no trust anchor is configured.\n\nverify_xml in Net::SAML2::Role::VerifyXML runs \"return if !$anchors \u0026\u0026 !$cacert;\" as soon as the XML::Sig check succeeds, and that check uses the X.509 certificate taken from the response\u0027s own dsig:KeyInfo/dsig:X509Certificate element, so an unanchored response is checked only against the key it carries. Binding::POST declares cacert as an optional Maybe[Str] with no default, so a POST binding built without one takes that path, and _verify_encrypted_assertion returns early the same way with \"return $xml unless $cacert;\".\n\nAny caller that constructs Binding::POST or calls Assertion-\u003enew_from_xml without a cacert, cert_text, or anchors argument accepts a response signed by an attacker generated key whose self-signed certificate is embedded in that response, authenticating an arbitrary assertion."
    }
  ],
  "id": "CVE-2026-18089",
  "lastModified": "2026-08-06T18:36:40.763",
  "metrics": {
    "cvssMetricV31": [
      {
        "cvssData": {
          "attackComplexity": "LOW",
          "attackVector": "NETWORK",
          "availabilityImpact": "NONE",
          "baseScore": 7.5,
          "baseSeverity": "HIGH",
          "confidentialityImpact": "NONE",
          "integrityImpact": "HIGH",
          "privilegesRequired": "NONE",
          "scope": "UNCHANGED",
          "userInteraction": "NONE",
          "vectorString": "CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:N/I:H/A:N",
          "version": "3.1"
        },
        "exploitabilityScore": 3.9,
        "impactScore": 3.6,
        "source": "134c704f-9b21-4f2e-91b3-4a467353bcc0",
        "type": "Secondary"
      }
    ],
    "ssvcV203": [
      {
        "source": "134c704f-9b21-4f2e-91b3-4a467353bcc0",
        "ssvcData": {
          "id": "CVE-2026-18089",
          "options": [
            {
              "exploitation": "none"
            },
            {
              "automatable": "yes"
            },
            {
              "technicalImpact": "partial"
            }
          ],
          "role": "CISA Coordinator",
          "timestamp": "2026-08-03T19:56:09.872860Z",
          "version": "2.0.3"
        }
      }
    ]
  },
  "published": "2026-08-03T14:16:24.890",
  "references": [
    {
      "source": "9b29abf9-4ab0-4765-b253-1875cd9b441e",
      "tags": [
        "Product"
      ],
      "url": "https://metacpan.org/release/TIMLEGGE/Net-SAML2-0.85/source/lib/Net/SAML2/Binding/POST.pm#L21"
    },
    {
      "source": "9b29abf9-4ab0-4765-b253-1875cd9b441e",
      "tags": [
        "Product"
      ],
      "url": "https://metacpan.org/release/TIMLEGGE/Net-SAML2-0.85/source/lib/Net/SAML2/Protocol/Assertion.pm#L84"
    },
    {
      "source": "9b29abf9-4ab0-4765-b253-1875cd9b441e",
      "tags": [
        "Product"
      ],
      "url": "https://metacpan.org/release/TIMLEGGE/Net-SAML2-0.85/source/lib/Net/SAML2/Role/VerifyXML.pm#L32"
    },
    {
      "source": "9b29abf9-4ab0-4765-b253-1875cd9b441e",
      "tags": [
        "Release Notes"
      ],
      "url": "https://metacpan.org/release/TIMLEGGE/Net-SAML2-0.88/source/Changes"
    }
  ],
  "sourceIdentifier": "9b29abf9-4ab0-4765-b253-1875cd9b441e",
  "vulnStatus": "Analyzed",
  "weaknesses": [
    {
      "description": [
        {
          "lang": "en",
          "value": "CWE-295"
        },
        {
          "lang": "en",
          "value": "CWE-347"
        }
      ],
      "source": "9b29abf9-4ab0-4765-b253-1875cd9b441e",
      "type": "Secondary"
    }
  ]
}



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