Vulnerability-Lookup

CVE-2026-18089 (GCVE-0-2026-18089)

Vulnerability from cvelistv5 – Published: 2026-08-03 12:42 – Updated: 2026-08-03 19:56

Title

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

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.

Severity

7.5 (High)


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

SSVC

Exploitation: none Automatable: yes Technical Impact: partial

CISA Coordinator · CISA-ADP (v2.0.3)

Decision recorded 2026-08-03 19:56 UTC

CWE

CWE-347 - Improper Verification of Cryptographic Signature
CWE-295 - Improper Certificate Validation

Assigner

CPANSec redhat root

References

4 references

URL	Tags
https://metacpan.org/release/TIMLEGGE/Net-SAML2-0…	release-notes
https://metacpan.org/release/TIMLEGGE/Net-SAML2-0…
https://metacpan.org/release/TIMLEGGE/Net-SAML2-0…
https://metacpan.org/release/TIMLEGGE/Net-SAML2-0…

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

{
  "containers": {
    "adp": [
      {
        "metrics": [
          {
            "cvssV3_1": {
              "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"
            }
          },
          {
            "other": {
              "content": {
                "id": "CVE-2026-18089",
                "options": [
                  {
                    "Exploitation": "none"
                  },
                  {
                    "Automatable": "yes"
                  },
                  {
                    "Technical Impact": "partial"
                  }
                ],
                "role": "CISA Coordinator",
                "timestamp": "2026-08-03T19:56:09.872860Z",
                "version": "2.0.3"
              },
              "type": "ssvc"
            }
          }
        ],
        "providerMetadata": {
          "dateUpdated": "2026-08-03T19:56:33.033Z",
          "orgId": "134c704f-9b21-4f2e-91b3-4a467353bcc0",
          "shortName": "CISA-ADP"
        },
        "title": "CISA ADP Vulnrichment"
      }
    ],
    "cna": {
      "affected": [
        {
          "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"
            }
          ]
        }
      ],
      "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."
        }
      ],
      "impacts": [
        {
          "capecId": "CAPEC-115",
          "descriptions": [
            {
              "lang": "en",
              "value": "CAPEC-115 Authentication Bypass"
            }
          ]
        }
      ],
      "problemTypes": [
        {
          "descriptions": [
            {
              "cweId": "CWE-347",
              "description": "CWE-347 Improper Verification of Cryptographic Signature",
              "lang": "en",
              "type": "CWE"
            }
          ]
        },
        {
          "descriptions": [
            {
              "cweId": "CWE-295",
              "description": "CWE-295 Improper Certificate Validation",
              "lang": "en",
              "type": "CWE"
            }
          ]
        }
      ],
      "providerMetadata": {
        "dateUpdated": "2026-08-03T12:42:08.879Z",
        "orgId": "9b29abf9-4ab0-4765-b253-1875cd9b441e",
        "shortName": "CPANSec"
      },
      "references": [
        {
          "tags": [
            "release-notes"
          ],
          "url": "https://metacpan.org/release/TIMLEGGE/Net-SAML2-0.88/source/Changes"
        },
        {
          "url": "https://metacpan.org/release/TIMLEGGE/Net-SAML2-0.85/source/lib/Net/SAML2/Role/VerifyXML.pm#L32"
        },
        {
          "url": "https://metacpan.org/release/TIMLEGGE/Net-SAML2-0.85/source/lib/Net/SAML2/Binding/POST.pm#L21"
        },
        {
          "url": "https://metacpan.org/release/TIMLEGGE/Net-SAML2-0.85/source/lib/Net/SAML2/Protocol/Assertion.pm#L84"
        }
      ],
      "solutions": [
        {
          "lang": "en",
          "value": "Upgrade to Net::SAML2 0.86 or later, which requires a cacert or cert_text trust anchor before a response or assertion signature is verified."
        }
      ],
      "source": {
        "discovery": "UNKNOWN"
      },
      "timeline": [
        {
          "lang": "en",
          "time": "2026-07-31T00:00:00.000Z",
          "value": "Version 0.86 released with fix."
        },
        {
          "lang": "en",
          "time": "2026-07-31T00:00:00.000Z",
          "value": "Version 0.88 released, re-issuing 0.86 with a corrected version number."
        }
      ],
      "title": "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",
      "workarounds": [
        {
          "lang": "en",
          "value": "For deployments that cannot upgrade, construct Net::SAML2::Binding::POST, and call Net::SAML2::Protocol::Assertion-\u003enew_from_xml, with a cacert, cert_text, or anchors argument identifying the IdP signing certificate."
        }
      ],
      "x_generator": {
        "engine": "cpansec-cna-tool 0.1"
      }
    }
  },
  "cveMetadata": {
    "assignerOrgId": "9b29abf9-4ab0-4765-b253-1875cd9b441e",
    "assignerShortName": "CPANSec",
    "cveId": "CVE-2026-18089",
    "datePublished": "2026-08-03T12:42:08.879Z",
    "dateReserved": "2026-07-28T16:26:10.967Z",
    "dateUpdated": "2026-08-03T19:56:33.033Z",
    "state": "PUBLISHED"
  },
  "dataType": "CVE_RECORD",
  "dataVersion": "5.2",
  "vulnerability-lookup:meta": {
    "epss": {
      "cve": "CVE-2026-18089",
      "date": "2026-09-17",
      "epss": "0.00175",
      "percentile": "0.07295"
    },
    "nvd": "{\"cve\":{\"id\":\"CVE-2026-18089\",\"sourceIdentifier\":\"9b29abf9-4ab0-4765-b253-1875cd9b441e\",\"published\":\"2026-08-03T14:16:24.890\",\"lastModified\":\"2026-08-06T18:36:40.763\",\"vulnStatus\":\"Analyzed\",\"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.\"}],\"affected\":[{\"source\":\"9b29abf9-4ab0-4765-b253-1875cd9b441e\",\"affectedData\":[{\"vendor\":\"TIMLEGGE\",\"product\":\"Net::SAML2\",\"defaultStatus\":\"unaffected\",\"collectionURL\":\"https://cpan.org/modules\",\"packageName\":\"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\",\"versions\":[{\"version\":\"0\",\"lessThan\":\"0.86\",\"versionType\":\"custom\",\"status\":\"affected\"}]}]}],\"metrics\":{\"cvssMetricV31\":[{\"source\":\"134c704f-9b21-4f2e-91b3-4a467353bcc0\",\"type\":\"Secondary\",\"cvssData\":{\"version\":\"3.1\",\"vectorString\":\"CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:N/I:H/A:N\",\"baseScore\":7.5,\"baseSeverity\":\"HIGH\",\"attackVector\":\"NETWORK\",\"attackComplexity\":\"LOW\",\"privilegesRequired\":\"NONE\",\"userInteraction\":\"NONE\",\"scope\":\"UNCHANGED\",\"confidentialityImpact\":\"NONE\",\"integrityImpact\":\"HIGH\",\"availabilityImpact\":\"NONE\"},\"exploitabilityScore\":3.9,\"impactScore\":3.6}],\"ssvcV203\":[{\"source\":\"134c704f-9b21-4f2e-91b3-4a467353bcc0\",\"ssvcData\":{\"timestamp\":\"2026-08-03T19:56:09.872860Z\",\"id\":\"CVE-2026-18089\",\"options\":[{\"exploitation\":\"none\"},{\"automatable\":\"yes\"},{\"technicalImpact\":\"partial\"}],\"role\":\"CISA Coordinator\",\"version\":\"2.0.3\"}}]},\"weaknesses\":[{\"source\":\"9b29abf9-4ab0-4765-b253-1875cd9b441e\",\"type\":\"Secondary\",\"description\":[{\"lang\":\"en\",\"value\":\"CWE-295\"},{\"lang\":\"en\",\"value\":\"CWE-347\"}]}],\"configurations\":[{\"nodes\":[{\"operator\":\"OR\",\"negate\":false,\"cpeMatch\":[{\"vulnerable\":true,\"criteria\":\"cpe:2.3:a:timlegge:net\\\\:\\\\:saml2:*:*:*:*:*:perl:*:*\",\"versionEndExcluding\":\"0.86\",\"matchCriteriaId\":\"69FF1709-62F7-4E8C-B90D-ABFA96B07FF1\"}]}]}],\"references\":[{\"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\":[\"Product\"]},{\"url\":\"https://metacpan.org/release/TIMLEGGE/Net-SAML2-0.88/source/Changes\",\"source\":\"9b29abf9-4ab0-4765-b253-1875cd9b441e\",\"tags\":[\"Release Notes\"]}]}}",
    "vulnrichment": {
      "containers": "{\"adp\": [{\"title\": \"CISA ADP Vulnrichment\", \"metrics\": [{\"cvssV3_1\": {\"scope\": \"UNCHANGED\", \"version\": \"3.1\", \"baseScore\": 7.5, \"attackVector\": \"NETWORK\", \"baseSeverity\": \"HIGH\", \"vectorString\": \"CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:N/I:H/A:N\", \"integrityImpact\": \"HIGH\", \"userInteraction\": \"NONE\", \"attackComplexity\": \"LOW\", \"availabilityImpact\": \"NONE\", \"privilegesRequired\": \"NONE\", \"confidentialityImpact\": \"NONE\"}}, {\"other\": {\"type\": \"ssvc\", \"content\": {\"id\": \"CVE-2026-18089\", \"role\": \"CISA Coordinator\", \"options\": [{\"Exploitation\": \"none\"}, {\"Automatable\": \"yes\"}, {\"Technical Impact\": \"partial\"}], \"version\": \"2.0.3\", \"timestamp\": \"2026-08-03T19:56:09.872860Z\"}}}], \"providerMetadata\": {\"orgId\": \"134c704f-9b21-4f2e-91b3-4a467353bcc0\", \"shortName\": \"CISA-ADP\", \"dateUpdated\": \"2026-08-03T19:56:28.831Z\"}}], \"cna\": {\"title\": \"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\", \"source\": {\"discovery\": \"UNKNOWN\"}, \"impacts\": [{\"capecId\": \"CAPEC-115\", \"descriptions\": [{\"lang\": \"en\", \"value\": \"CAPEC-115 Authentication Bypass\"}]}], \"affected\": [{\"repo\": \"https://github.com/perl-net-saml2/perl-Net-SAML2\", \"vendor\": \"TIMLEGGE\", \"product\": \"Net::SAML2\", \"versions\": [{\"status\": \"affected\", \"version\": \"0\", \"lessThan\": \"0.86\", \"versionType\": \"custom\"}], \"packageName\": \"Net-SAML2\", \"programFiles\": [\"lib/Net/SAML2/Role/VerifyXML.pm\", \"lib/Net/SAML2/Binding/POST.pm\", \"lib/Net/SAML2/Protocol/Assertion.pm\"], \"collectionURL\": \"https://cpan.org/modules\", \"defaultStatus\": \"unaffected\", \"programRoutines\": [{\"name\": \"Net::SAML2::Role::VerifyXML::verify_xml\"}, {\"name\": \"Net::SAML2::Binding::POST::handle_response\"}, {\"name\": \"Net::SAML2::Protocol::Assertion::_verify_encrypted_assertion\"}]}], \"timeline\": [{\"lang\": \"en\", \"time\": \"2026-07-31T00:00:00.000Z\", \"value\": \"Version 0.86 released with fix.\"}, {\"lang\": \"en\", \"time\": \"2026-07-31T00:00:00.000Z\", \"value\": \"Version 0.88 released, re-issuing 0.86 with a corrected version number.\"}], \"solutions\": [{\"lang\": \"en\", \"value\": \"Upgrade to Net::SAML2 0.86 or later, which requires a cacert or cert_text trust anchor before a response or assertion signature is verified.\"}], \"references\": [{\"url\": \"https://metacpan.org/release/TIMLEGGE/Net-SAML2-0.88/source/Changes\", \"tags\": [\"release-notes\"]}, {\"url\": \"https://metacpan.org/release/TIMLEGGE/Net-SAML2-0.85/source/lib/Net/SAML2/Role/VerifyXML.pm#L32\"}, {\"url\": \"https://metacpan.org/release/TIMLEGGE/Net-SAML2-0.85/source/lib/Net/SAML2/Binding/POST.pm#L21\"}, {\"url\": \"https://metacpan.org/release/TIMLEGGE/Net-SAML2-0.85/source/lib/Net/SAML2/Protocol/Assertion.pm#L84\"}], \"workarounds\": [{\"lang\": \"en\", \"value\": \"For deployments that cannot upgrade, construct Net::SAML2::Binding::POST, and call Net::SAML2::Protocol::Assertion-\u003enew_from_xml, with a cacert, cert_text, or anchors argument identifying the IdP signing certificate.\"}], \"x_generator\": {\"engine\": \"cpansec-cna-tool 0.1\"}, \"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.\"}], \"problemTypes\": [{\"descriptions\": [{\"lang\": \"en\", \"type\": \"CWE\", \"cweId\": \"CWE-347\", \"description\": \"CWE-347 Improper Verification of Cryptographic Signature\"}]}, {\"descriptions\": [{\"lang\": \"en\", \"type\": \"CWE\", \"cweId\": \"CWE-295\", \"description\": \"CWE-295 Improper Certificate Validation\"}]}], \"providerMetadata\": {\"orgId\": \"9b29abf9-4ab0-4765-b253-1875cd9b441e\", \"shortName\": \"CPANSec\", \"dateUpdated\": \"2026-08-03T12:42:08.879Z\"}}}",
      "cveMetadata": "{\"cveId\": \"CVE-2026-18089\", \"state\": \"PUBLISHED\", \"dateUpdated\": \"2026-08-03T19:56:33.033Z\", \"dateReserved\": \"2026-07-28T16:26:10.967Z\", \"assignerOrgId\": \"9b29abf9-4ab0-4765-b253-1875cd9b441e\", \"datePublished\": \"2026-08-03T12:42:08.879Z\", \"assignerShortName\": \"CPANSec\"}",
      "dataType": "CVE_RECORD",
      "dataVersion": "5.2"
    }
  }
}

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

References

URL	Tags
9b29abf9-4ab0-4765-b253-1875cd9b441e	https://metacpan.org/release/TIMLEGGE/Net-SAML2-0.85/source/lib/Net/SAML2/Binding/POST.pm#L21	Product
9b29abf9-4ab0-4765-b253-1875cd9b441e	https://metacpan.org/release/TIMLEGGE/Net-SAML2-0.85/source/lib/Net/SAML2/Protocol/Assertion.pm#L84	Product
9b29abf9-4ab0-4765-b253-1875cd9b441e	https://metacpan.org/release/TIMLEGGE/Net-SAML2-0.85/source/lib/Net/SAML2/Role/VerifyXML.pm#L32	Product
9b29abf9-4ab0-4765-b253-1875cd9b441e	https://metacpan.org/release/TIMLEGGE/Net-SAML2-0.88/source/Changes	Release Notes

Impacted products

	Vendor	Product	Version
	timlegge	net\	\

JSON

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"
    }
  ]
}

GHSA-P5J9-P2W8-Q5RW

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

Details

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.

Severity

7.5 (High)


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

Show details on source website

JSON

To clipboard

{
  "affected": [],
  "aliases": [
    "CVE-2026-18089"
  ],
  "database_specific": {
    "cwe_ids": [
      "CWE-295"
    ],
    "github_reviewed": false,
    "github_reviewed_at": null,
    "nvd_published_at": "2026-08-03T14:16:24Z",
    "severity": "HIGH"
  },
  "details": "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": "GHSA-p5j9-p2w8-q5rw",
  "modified": "2026-08-03T21:31:34Z",
  "published": "2026-08-03T15:32:47Z",
  "references": [
    {
      "type": "ADVISORY",
      "url": "https://nvd.nist.gov/vuln/detail/CVE-2026-18089"
    },
    {
      "type": "WEB",
      "url": "https://metacpan.org/release/TIMLEGGE/Net-SAML2-0.85/source/lib/Net/SAML2/Binding/POST.pm#L21"
    },
    {
      "type": "WEB",
      "url": "https://metacpan.org/release/TIMLEGGE/Net-SAML2-0.85/source/lib/Net/SAML2/Protocol/Assertion.pm#L84"
    },
    {
      "type": "WEB",
      "url": "https://metacpan.org/release/TIMLEGGE/Net-SAML2-0.85/source/lib/Net/SAML2/Role/VerifyXML.pm#L32"
    },
    {
      "type": "WEB",
      "url": "https://metacpan.org/release/TIMLEGGE/Net-SAML2-0.88/source/Changes"
    }
  ],
  "schema_version": "1.4.0",
  "severity": [
    {
      "score": "CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:N/I:H/A:N",
      "type": "CVSS_V3"
    }
  ]
}

Sightings

Author	Source	Type	Date	Other

Nomenclature

Seen: The vulnerability was mentioned, discussed, or observed by the user.
Confirmed: The vulnerability has been validated from an analyst's perspective.
Published Proof of Concept: A public proof of concept is available for this vulnerability.
Exploited: The vulnerability was observed as exploited by the user who reported the sighting.
Patched: The vulnerability was observed as successfully patched by the user who reported the sighting.
Not exploited: The vulnerability was not observed as exploited by the user who reported the sighting.
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.

Detection rules are retrieved from Rulezet.

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.
Browse all ATT&CK techniques and the vulnerabilities related to each.

Related by attack behaviour

Vulnerabilities whose description is nearest to this one in the vector space of the CIRCL/vulnerability-attack-technique-biencoder model. This is a similarity search over the bi-encoder space (plain cosine), not a classification, and it has no measured accuracy.

Action not permitted

CVE-2026-18089 (GCVE-0-2026-18089)

FKIE_CVE-2026-18089

GHSA-P5J9-P2W8-Q5RW

Tags

Sightings

Nomenclature

Related by attack behaviour