Vulnerability-Lookup

CVE-2026-15981 (GCVE-0-2026-15981)

Vulnerability from cvelistv5 – Published: 2026-07-23 20:33 – Updated: 2026-07-23 20:33

Title

SAML Single Sign On <= 5.4.4 - Unauthenticated Authentication Bypass via SAMLResponse Parameter

Summary

The SAML Single Sign On – SSO Login plugin for WordPress is vulnerable to Authentication Bypass in all versions up to, and including, 5.4.4. This is due to the mo_saml_validate_signature() function performing a loose boolean check on the raw tri-state integer returned by PHP's openssl_verify(), causing an error return value of -1 to be evaluated as truthy and therefore treated as a successful signature verification. This makes it possible for unauthenticated attackers to log in as any existing WordPress user, including administrators, by submitting a crafted SAMLResponse containing an attacker-controlled NameID and a deliberately malformed signature value that triggers an OpenSSL processing error — bypassing verification entirely and resulting in wp_set_auth_cookie() being called for the targeted account.

Severity

9.8 (Critical)


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

CWE

CWE-287 - Improper Authentication

Assigner

Wordfence

References

7 references

URL	Tags
https://www.wordfence.com/threat-intel/vulnerabil…
https://plugins.trac.wordpress.org/browser/minior…
https://plugins.trac.wordpress.org/browser/minior…
https://plugins.trac.wordpress.org/browser/minior…
https://plugins.trac.wordpress.org/browser/minior…
https://plugins.trac.wordpress.org/browser/minior…
https://plugins.trac.wordpress.org/changeset/3611…

Impacted products

1 product

Vendor	Product	Version
cyberlord92	SAML Single Sign On – SSO Login	Affected: 0 , ≤ 5.4.4 (semver)

Credits

Supakiad S. (m3ez)

Show details on NVD website

JSON

To clipboard

{
  "containers": {
    "cna": {
      "affected": [
        {
          "defaultStatus": "unaffected",
          "product": "SAML Single Sign On \u2013 SSO Login",
          "vendor": "cyberlord92",
          "versions": [
            {
              "lessThanOrEqual": "5.4.4",
              "status": "affected",
              "version": "0",
              "versionType": "semver"
            }
          ]
        }
      ],
      "credits": [
        {
          "lang": "en",
          "type": "finder",
          "value": "Supakiad S. (m3ez)"
        }
      ],
      "descriptions": [
        {
          "lang": "en",
          "value": "The SAML Single Sign On \u2013 SSO Login plugin for WordPress is vulnerable to Authentication Bypass in all versions up to, and including, 5.4.4. This is due to the mo_saml_validate_signature() function performing a loose boolean check on the raw tri-state integer returned by PHP\u0027s openssl_verify(), causing an error return value of -1 to be evaluated as truthy and therefore treated as a successful signature verification. This makes it possible for unauthenticated attackers to log in as any existing WordPress user, including administrators, by submitting a crafted SAMLResponse containing an attacker-controlled NameID and a deliberately malformed signature value that triggers an OpenSSL processing error \u2014 bypassing verification entirely and resulting in wp_set_auth_cookie() being called for the targeted account."
        }
      ],
      "metrics": [
        {
          "cvssV3_1": {
            "baseScore": 9.8,
            "baseSeverity": "CRITICAL",
            "vectorString": "CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:H/I:H/A:H",
            "version": "3.1"
          }
        }
      ],
      "problemTypes": [
        {
          "descriptions": [
            {
              "cweId": "CWE-287",
              "description": "CWE-287 Improper Authentication",
              "lang": "en",
              "type": "CWE"
            }
          ]
        }
      ],
      "providerMetadata": {
        "dateUpdated": "2026-07-23T20:33:51.362Z",
        "orgId": "b15e7b5b-3da4-40ae-a43c-f7aa60e62599",
        "shortName": "Wordfence"
      },
      "references": [
        {
          "url": "https://www.wordfence.com/threat-intel/vulnerabilities/id/b412f60f-61ea-47b1-a3ef-17275f7951df?source=cve"
        },
        {
          "url": "https://plugins.trac.wordpress.org/browser/miniorange-saml-20-single-sign-on/tags/5.4.4/class-mo-saml-login-validate.php#L118"
        },
        {
          "url": "https://plugins.trac.wordpress.org/browser/miniorange-saml-20-single-sign-on/tags/5.4.4/class-mo-saml-utilities.php#L403"
        },
        {
          "url": "https://plugins.trac.wordpress.org/browser/miniorange-saml-20-single-sign-on/tags/5.4.4/includes/lib/SAML2Core/class-mo-saml-xml-security-dsig.php#L938"
        },
        {
          "url": "https://plugins.trac.wordpress.org/browser/miniorange-saml-20-single-sign-on/tags/5.4.4/includes/lib/SAML2Core/class-mo-saml-xml-security-key.php#L621"
        },
        {
          "url": "https://plugins.trac.wordpress.org/browser/miniorange-saml-20-single-sign-on/tags/5.4.4/class-mo-saml-login-validate.php#L541"
        },
        {
          "url": "https://plugins.trac.wordpress.org/changeset/3611421/miniorange-saml-20-single-sign-on"
        }
      ],
      "timeline": [
        {
          "lang": "en",
          "time": "2026-07-16T17:11:08.000Z",
          "value": "Vendor Notified"
        },
        {
          "lang": "en",
          "time": "2026-07-23T08:24:20.000Z",
          "value": "Disclosed"
        }
      ],
      "title": "SAML Single Sign On \u003c= 5.4.4 - Unauthenticated Authentication Bypass via SAMLResponse Parameter"
    }
  },
  "cveMetadata": {
    "assignerOrgId": "b15e7b5b-3da4-40ae-a43c-f7aa60e62599",
    "assignerShortName": "Wordfence",
    "cveId": "CVE-2026-15981",
    "datePublished": "2026-07-23T20:33:51.362Z",
    "dateReserved": "2026-07-16T16:55:30.527Z",
    "dateUpdated": "2026-07-23T20:33:51.362Z",
    "state": "PUBLISHED"
  },
  "dataType": "CVE_RECORD",
  "dataVersion": "5.2",
  "vulnerability-lookup:meta": {
    "epss": {
      "cve": "CVE-2026-15981",
      "date": "2026-07-24",
      "epss": "0.00547",
      "percentile": "0.4252"
    },
    "nvd": "{\"cve\":{\"id\":\"CVE-2026-15981\",\"sourceIdentifier\":\"security@wordfence.com\",\"published\":\"2026-07-23T21:17:03.220\",\"lastModified\":\"2026-07-23T21:17:03.220\",\"vulnStatus\":\"Received\",\"cveTags\":[],\"descriptions\":[{\"lang\":\"en\",\"value\":\"The SAML Single Sign On \u2013 SSO Login plugin for WordPress is vulnerable to Authentication Bypass in all versions up to, and including, 5.4.4. This is due to the mo_saml_validate_signature() function performing a loose boolean check on the raw tri-state integer returned by PHP\u0027s openssl_verify(), causing an error return value of -1 to be evaluated as truthy and therefore treated as a successful signature verification. This makes it possible for unauthenticated attackers to log in as any existing WordPress user, including administrators, by submitting a crafted SAMLResponse containing an attacker-controlled NameID and a deliberately malformed signature value that triggers an OpenSSL processing error \u2014 bypassing verification entirely and resulting in wp_set_auth_cookie() being called for the targeted account.\"}],\"affected\":[{\"source\":\"security@wordfence.com\",\"affectedData\":[{\"vendor\":\"cyberlord92\",\"product\":\"SAML Single Sign On \u2013 SSO Login\",\"defaultStatus\":\"unaffected\",\"versions\":[{\"version\":\"0\",\"lessThanOrEqual\":\"5.4.4\",\"versionType\":\"semver\",\"status\":\"affected\"}]}]}],\"metrics\":{\"cvssMetricV31\":[{\"source\":\"security@wordfence.com\",\"type\":\"Primary\",\"cvssData\":{\"version\":\"3.1\",\"vectorString\":\"CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:H/I:H/A:H\",\"baseScore\":9.8,\"baseSeverity\":\"CRITICAL\",\"attackVector\":\"NETWORK\",\"attackComplexity\":\"LOW\",\"privilegesRequired\":\"NONE\",\"userInteraction\":\"NONE\",\"scope\":\"UNCHANGED\",\"confidentialityImpact\":\"HIGH\",\"integrityImpact\":\"HIGH\",\"availabilityImpact\":\"HIGH\"},\"exploitabilityScore\":3.9,\"impactScore\":5.9}]},\"weaknesses\":[{\"source\":\"security@wordfence.com\",\"type\":\"Primary\",\"description\":[{\"lang\":\"en\",\"value\":\"CWE-287\"}]}],\"references\":[{\"url\":\"https://plugins.trac.wordpress.org/browser/miniorange-saml-20-single-sign-on/tags/5.4.4/class-mo-saml-login-validate.php#L118\",\"source\":\"security@wordfence.com\"},{\"url\":\"https://plugins.trac.wordpress.org/browser/miniorange-saml-20-single-sign-on/tags/5.4.4/class-mo-saml-login-validate.php#L541\",\"source\":\"security@wordfence.com\"},{\"url\":\"https://plugins.trac.wordpress.org/browser/miniorange-saml-20-single-sign-on/tags/5.4.4/class-mo-saml-utilities.php#L403\",\"source\":\"security@wordfence.com\"},{\"url\":\"https://plugins.trac.wordpress.org/browser/miniorange-saml-20-single-sign-on/tags/5.4.4/includes/lib/SAML2Core/class-mo-saml-xml-security-dsig.php#L938\",\"source\":\"security@wordfence.com\"},{\"url\":\"https://plugins.trac.wordpress.org/browser/miniorange-saml-20-single-sign-on/tags/5.4.4/includes/lib/SAML2Core/class-mo-saml-xml-security-key.php#L621\",\"source\":\"security@wordfence.com\"},{\"url\":\"https://plugins.trac.wordpress.org/changeset/3611421/miniorange-saml-20-single-sign-on\",\"source\":\"security@wordfence.com\"},{\"url\":\"https://www.wordfence.com/threat-intel/vulnerabilities/id/b412f60f-61ea-47b1-a3ef-17275f7951df?source=cve\",\"source\":\"security@wordfence.com\"}]}}"
  }
}

GHSA-WGJX-Q85H-87V2

Vulnerability from github – Published: 2026-07-23 21:31 – Updated: 2026-07-23 21:31

Details

Severity

9.8 (Critical)


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

Show details on source website

JSON

To clipboard

{
  "affected": [],
  "aliases": [
    "CVE-2026-15981"
  ],
  "database_specific": {
    "cwe_ids": [
      "CWE-287"
    ],
    "github_reviewed": false,
    "github_reviewed_at": null,
    "nvd_published_at": "2026-07-23T21:17:03Z",
    "severity": "CRITICAL"
  },
  "details": "The SAML Single Sign On \u2013 SSO Login plugin for WordPress is vulnerable to Authentication Bypass in all versions up to, and including, 5.4.4. This is due to the mo_saml_validate_signature() function performing a loose boolean check on the raw tri-state integer returned by PHP\u0027s openssl_verify(), causing an error return value of -1 to be evaluated as truthy and therefore treated as a successful signature verification. This makes it possible for unauthenticated attackers to log in as any existing WordPress user, including administrators, by submitting a crafted SAMLResponse containing an attacker-controlled NameID and a deliberately malformed signature value that triggers an OpenSSL processing error \u2014 bypassing verification entirely and resulting in wp_set_auth_cookie() being called for the targeted account.",
  "id": "GHSA-wgjx-q85h-87v2",
  "modified": "2026-07-23T21:31:02Z",
  "published": "2026-07-23T21:31:02Z",
  "references": [
    {
      "type": "ADVISORY",
      "url": "https://nvd.nist.gov/vuln/detail/CVE-2026-15981"
    },
    {
      "type": "WEB",
      "url": "https://plugins.trac.wordpress.org/browser/miniorange-saml-20-single-sign-on/tags/5.4.4/class-mo-saml-login-validate.php#L118"
    },
    {
      "type": "WEB",
      "url": "https://plugins.trac.wordpress.org/browser/miniorange-saml-20-single-sign-on/tags/5.4.4/class-mo-saml-login-validate.php#L541"
    },
    {
      "type": "WEB",
      "url": "https://plugins.trac.wordpress.org/browser/miniorange-saml-20-single-sign-on/tags/5.4.4/class-mo-saml-utilities.php#L403"
    },
    {
      "type": "WEB",
      "url": "https://plugins.trac.wordpress.org/browser/miniorange-saml-20-single-sign-on/tags/5.4.4/includes/lib/SAML2Core/class-mo-saml-xml-security-dsig.php#L938"
    },
    {
      "type": "WEB",
      "url": "https://plugins.trac.wordpress.org/browser/miniorange-saml-20-single-sign-on/tags/5.4.4/includes/lib/SAML2Core/class-mo-saml-xml-security-key.php#L621"
    },
    {
      "type": "WEB",
      "url": "https://plugins.trac.wordpress.org/changeset/3611421/miniorange-saml-20-single-sign-on"
    },
    {
      "type": "WEB",
      "url": "https://www.wordfence.com/threat-intel/vulnerabilities/id/b412f60f-61ea-47b1-a3ef-17275f7951df?source=cve"
    }
  ],
  "schema_version": "1.4.0",
  "severity": [
    {
      "score": "CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:H/I:H/A:H",
      "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.

Action not permitted

CVE-2026-15981 (GCVE-0-2026-15981)

GHSA-WGJX-Q85H-87V2

Tags

Sightings

Nomenclature