Vulnerability-Lookup

CVE-2026-49283 (GCVE-0-2026-49283)

Vulnerability from cvelistv5 – Published: 2026-08-19 14:47 – Updated: 2026-08-19 18:19

Title

SimpleSAMLphp HTTP-Artifact TLS validator confusion allows cross-IdP authentication bypass

Summary

The SimpleSAMLphp SAML2 library is a PHP library for SAML2 related functionality. Prior to versions 4.19.3, 4.20.2, 5.0.6, and 6.2.1, the HTTPArtifact::receive() flow can treat an unsigned embedded SAML Response as cryptographically valid for the wrong identity provider. SOAPClient::addSSLValidator() attaches a TLS-based validator to the outer SOAP ArtifactResponse, while the embedded Response receives a validator that delegates to the outer message and is later checked against metadata selected from the embedded response issuer rather than necessarily the artifact issuer. SOAPClient::validateSSL() returns normally when the TLS public key does not match the key being validated, and SAML2\Message::validate() treats a validator call that does not throw as successful. In a multi-IdP federation, a malicious or lower-trust IdP can therefore provide an ArtifactResponse containing an unsigned Response that claims a higher-trust victim IdP as issuer and authenticate as arbitrary users with attacker-chosen assertion attributes, NameID, and session data. This issue is fixed in versions 4.19.3, 4.20.2, 5.0.6, and 6.2.1.

Severity

8.7 (High)


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

SSVC

Exploitation: none Automatable: no Technical Impact: total

CISA Coordinator · CISA-ADP (v2.0.3)

Decision recorded 2026-08-19 18:16 UTC

CWE

CWE-295 - Improper Certificate Validation

Assigner

GitHub_M CNA under the mitre root

CNA scorecard C 72/100 over 7566 records in the last 180 days details

References

5 references

URL	Tags
https://github.com/simplesamlphp/saml2/security/a…	x_refsource_CONFIRM
https://github.com/simplesamlphp/saml2/commit/4a7…	x_refsource_MISC
https://github.com/simplesamlphp/saml2/commit/a2c…	x_refsource_MISC
https://github.com/simplesamlphp/saml2/commit/d5c…	x_refsource_MISC
https://github.com/simplesamlphp/saml2/commit/e2d…	x_refsource_MISC

Impacted products

1 product

Vendor	Product	Version	CPE status
simplesamlphp	saml2	Affected: < 4.19.3 Affected: >= 4.20.0, < 4.20.2 Affected: >= 5.0.0, < 5.0.6 Affected: >= 6.0.0, < 6.2.1	guessed

Show details on NVD website

JSON

To clipboard

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FKIE_CVE-2026-49283

Vulnerability from fkie_nvd - Published: 2026-08-19 15:17 - Updated: 2026-09-18 20:09

Severity

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

Summary

References

	URL	Tags
	security-advisories@github.com	https://github.com/simplesamlphp/saml2/commit/4a71b20d8d845579fd0a54d6449c265b40db459d
	security-advisories@github.com	https://github.com/simplesamlphp/saml2/commit/a2c1ac588c70d7b7998546cf32675fb113f22a5f
	security-advisories@github.com	https://github.com/simplesamlphp/saml2/commit/d5c213132ef671c0018a11252322034dbddd735a
	security-advisories@github.com	https://github.com/simplesamlphp/saml2/commit/e2df7992609964951b2a3e7d6566b7427b2a968f
	security-advisories@github.com	https://github.com/simplesamlphp/saml2/security/advisories/GHSA-6929-8p9f-26jx

Impacted products

	Vendor	Product	Version

JSON

To clipboard

{
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  "lastModified": "2026-09-18T20:09:01.757",
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          "options": [
            {
              "exploitation": "none"
            },
            {
              "automatable": "no"
            },
            {
              "technicalImpact": "total"
            }
          ],
          "role": "CISA Coordinator",
          "timestamp": "2026-08-19T18:16:10.690773Z",
          "version": "2.0.3"
        }
      }
    ]
  },
  "published": "2026-08-19T15:17:07.027",
  "references": [
    {
      "source": "security-advisories@github.com",
      "url": "https://github.com/simplesamlphp/saml2/commit/4a71b20d8d845579fd0a54d6449c265b40db459d"
    },
    {
      "source": "security-advisories@github.com",
      "url": "https://github.com/simplesamlphp/saml2/commit/a2c1ac588c70d7b7998546cf32675fb113f22a5f"
    },
    {
      "source": "security-advisories@github.com",
      "url": "https://github.com/simplesamlphp/saml2/commit/d5c213132ef671c0018a11252322034dbddd735a"
    },
    {
      "source": "security-advisories@github.com",
      "url": "https://github.com/simplesamlphp/saml2/commit/e2df7992609964951b2a3e7d6566b7427b2a968f"
    },
    {
      "source": "security-advisories@github.com",
      "url": "https://github.com/simplesamlphp/saml2/security/advisories/GHSA-6929-8p9f-26jx"
    }
  ],
  "sourceIdentifier": "security-advisories@github.com",
  "vulnStatus": "Deferred",
  "weaknesses": [
    {
      "description": [
        {
          "lang": "en",
          "value": "CWE-295"
        }
      ],
      "source": "security-advisories@github.com",
      "type": "Secondary"
    }
  ]
}

GHSA-6929-8P9F-26JX

Vulnerability from github – Published: 2026-07-02 20:25 – Updated: 2026-08-04 21:23

Summary

SimpleSAMLphp HTTP-Artifact TLS validator confusion allows cross-IdP authentication bypass

Details

Summary

SimpleSAMLphp's HTTP-Artifact receive path can treat an unsigned embedded SAML Response as cryptographically valid for the wrong IdP.

In the HTTPArtifact::receive() flow, the SOAP ArtifactResponse receives a TLS-based validator from SOAPClient::addSSLValidator(). The embedded SAML Response then receives a validator that delegates signature validation to that outer ArtifactResponse. Later, the SP validates the embedded Response against metadata selected from the embedded response issuer, not necessarily the artifact issuer.

The critical issue is that SOAPClient::validateSSL() returns normally when the TLS public key does not match the key currently being validated. SAML2\Message::validate() treats any validator call that does not throw an exception as successful. As a result, an ArtifactResponse obtained from one IdP can validate an unsigned embedded SAML Response that claims to be issued by a different IdP.

In a multi-IdP/federation deployment where a malicious or lower-trust IdP can issue an HTTP-Artifact response to an SP, this can allow the attacker to authenticate to the SP as arbitrary users from a higher-trust victim IdP.

Impact

A malicious or lower-trust IdP in the same SP/federation trust set can authenticate to the SP as users from another IdP when HTTP-Artifact is used. The attacker can choose assertion attributes, NameID, and session data in the forged unsigned assertion.

This is an authentication bypass and identity-provider impersonation issue. In realistic federations, the security boundary between IdPs matters: a compromised or low-assurance IdP should not be able to mint identities for a high-assurance IdP.

Severity

8.7 (High)


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

Show details on source website

JSON

To clipboard

{
  "affected": [
    {
      "package": {
        "ecosystem": "Packagist",
        "name": "simplesamlphp/saml2"
      },
      "ranges": [
        {
          "events": [
            {
              "introduced": "6.0.0"
            },
            {
              "fixed": "6.2.1"
            }
          ],
          "type": "ECOSYSTEM"
        }
      ]
    },
    {
      "package": {
        "ecosystem": "Packagist",
        "name": "simplesamlphp/saml2"
      },
      "ranges": [
        {
          "events": [
            {
              "introduced": "5.0.0"
            },
            {
              "fixed": "5.0.6"
            }
          ],
          "type": "ECOSYSTEM"
        }
      ]
    },
    {
      "package": {
        "ecosystem": "Packagist",
        "name": "simplesamlphp/saml2"
      },
      "ranges": [
        {
          "events": [
            {
              "introduced": "4.20.0"
            },
            {
              "fixed": "4.20.2"
            }
          ],
          "type": "ECOSYSTEM"
        }
      ]
    },
    {
      "package": {
        "ecosystem": "Packagist",
        "name": "simplesamlphp/saml2-legacy"
      },
      "ranges": [
        {
          "events": [
            {
              "introduced": "4.20.0"
            },
            {
              "fixed": "4.20.2"
            }
          ],
          "type": "ECOSYSTEM"
        }
      ]
    },
    {
      "package": {
        "ecosystem": "Packagist",
        "name": "simplesamlphp/saml2"
      },
      "ranges": [
        {
          "events": [
            {
              "introduced": "0"
            },
            {
              "fixed": "4.19.3"
            }
          ],
          "type": "ECOSYSTEM"
        }
      ]
    },
    {
      "package": {
        "ecosystem": "Packagist",
        "name": "simplesamlphp/saml2-legacy"
      },
      "ranges": [
        {
          "events": [
            {
              "introduced": "0"
            },
            {
              "fixed": "4.19.3"
            }
          ],
          "type": "ECOSYSTEM"
        }
      ]
    }
  ],
  "aliases": [
    "CVE-2026-49283"
  ],
  "database_specific": {
    "cwe_ids": [
      "CWE-295"
    ],
    "github_reviewed": true,
    "github_reviewed_at": "2026-07-02T20:25:56Z",
    "nvd_published_at": null,
    "severity": "HIGH"
  },
  "details": "## Summary\n\nSimpleSAMLphp\u0027s HTTP-Artifact receive path can treat an unsigned embedded SAML `Response` as cryptographically valid for the wrong IdP.\n\nIn the `HTTPArtifact::receive()` flow, the SOAP `ArtifactResponse` receives a TLS-based validator from `SOAPClient::addSSLValidator()`. The embedded SAML `Response` then receives a validator that delegates signature validation to that outer `ArtifactResponse`. Later, the SP validates the embedded `Response` against metadata selected from the embedded response issuer, not necessarily the artifact issuer.\n\nThe critical issue is that `SOAPClient::validateSSL()` returns normally when the TLS public key does not match the key currently being validated. `SAML2\\Message::validate()` treats any validator call that does not throw an exception as successful. As a result, an `ArtifactResponse` obtained from one IdP can validate an unsigned embedded SAML `Response` that claims to be issued by a different IdP.\n\nIn a multi-IdP/federation deployment where a malicious or lower-trust IdP can issue an HTTP-Artifact response to an SP, this can allow the attacker to authenticate to the SP as arbitrary users from a higher-trust victim IdP.\n\n## Impact\n\nA malicious or lower-trust IdP in the same SP/federation trust set can authenticate to the SP as users from another IdP when HTTP-Artifact is used. The attacker can choose assertion attributes, `NameID`, and session data in the forged unsigned assertion.\n\nThis is an authentication bypass and identity-provider impersonation issue. In realistic federations, the security boundary between IdPs matters: a compromised or low-assurance IdP should not be able to mint identities for a high-assurance IdP.",
  "id": "GHSA-6929-8p9f-26jx",
  "modified": "2026-08-04T21:23:56Z",
  "published": "2026-07-02T20:25:56Z",
  "references": [
    {
      "type": "WEB",
      "url": "https://github.com/simplesamlphp/saml2/security/advisories/GHSA-6929-8p9f-26jx"
    },
    {
      "type": "PACKAGE",
      "url": "https://github.com/simplesamlphp/saml2"
    }
  ],
  "schema_version": "1.4.0",
  "severity": [
    {
      "score": "CVSS:3.1/AV:N/AC:L/PR:H/UI:N/S:C/C:H/I:H/A:N",
      "type": "CVSS_V3"
    }
  ],
  "summary": "SimpleSAMLphp HTTP-Artifact TLS validator confusion allows cross-IdP authentication bypass"
}

UBUNTU-CVE-2026-49283 (CVE-2026-49283)

Vulnerability from osv_ubuntu – Published: 2026-08-19 15:17 – Updated: 2026-09-15 17:47 – Source website

Details

Severity

8.7 (High)


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

N/A (UNKNOWN)


                    
                      medium

References

URL

Type

	https://ubuntu.com/security/CVE-2026-49283	REPORT
	https://www.cve.org/CVERecord?id=CVE-2026-49283	REPORT

JSON

To clipboard

{
  "affected": [
    {
      "ecosystem_specific": {
        "binaries": [
          {
            "binary_name": "simplesamlphp",
            "binary_version": "1.14.0-1ubuntu2+esm1"
          }
        ]
      },
      "package": {
        "ecosystem": "Ubuntu:Pro:16.04:LTS",
        "name": "simplesamlphp",
        "purl": "pkg:deb/ubuntu/simplesamlphp@1.14.0-1ubuntu2+esm1?arch=source\u0026distro=esm-apps-legacy/xenial"
      },
      "ranges": [
        {
          "events": [
            {
              "introduced": "0"
            }
          ],
          "type": "ECOSYSTEM"
        }
      ],
      "versions": [
        "1.13.2-1",
        "1.14.0-1",
        "1.14.0-1ubuntu2",
        "1.14.0-1ubuntu2+esm1"
      ]
    },
    {
      "ecosystem_specific": {
        "binaries": [
          {
            "binary_name": "simplesamlphp",
            "binary_version": "1.15.3-1ubuntu0.1~esm1"
          }
        ]
      },
      "package": {
        "ecosystem": "Ubuntu:Pro:18.04:LTS",
        "name": "simplesamlphp",
        "purl": "pkg:deb/ubuntu/simplesamlphp@1.15.3-1ubuntu0.1~esm1?arch=source\u0026distro=esm-apps/bionic"
      },
      "ranges": [
        {
          "events": [
            {
              "introduced": "0"
            }
          ],
          "type": "ECOSYSTEM"
        }
      ],
      "versions": [
        "1.14.15-1",
        "1.15.0-1",
        "1.15.1-1",
        "1.15.2-1",
        "1.15.3-1",
        "1.15.3-1ubuntu0.1~esm1"
      ]
    },
    {
      "ecosystem_specific": {
        "binaries": [
          {
            "binary_name": "simplesamlphp",
            "binary_version": "1.18.4-1ubuntu0.1~esm1"
          }
        ]
      },
      "package": {
        "ecosystem": "Ubuntu:Pro:20.04:LTS",
        "name": "simplesamlphp",
        "purl": "pkg:deb/ubuntu/simplesamlphp@1.18.4-1ubuntu0.1~esm1?arch=source\u0026distro=esm-apps/focal"
      },
      "ranges": [
        {
          "events": [
            {
              "introduced": "0"
            }
          ],
          "type": "ECOSYSTEM"
        }
      ],
      "versions": [
        "1.17.5-1",
        "1.17.6-1",
        "1.17.6-2",
        "1.18.1-1",
        "1.18.4-1",
        "1.18.4-1ubuntu0.1~esm1"
      ]
    },
    {
      "ecosystem_specific": {
        "binaries": [
          {
            "binary_name": "simplesamlphp",
            "binary_version": "1.19.1-1.1ubuntu0.1~esm1"
          }
        ]
      },
      "package": {
        "ecosystem": "Ubuntu:Pro:22.04:LTS",
        "name": "simplesamlphp",
        "purl": "pkg:deb/ubuntu/simplesamlphp@1.19.1-1.1ubuntu0.1~esm1?arch=source\u0026distro=esm-apps/jammy"
      },
      "ranges": [
        {
          "events": [
            {
              "introduced": "0"
            }
          ],
          "type": "ECOSYSTEM"
        }
      ],
      "versions": [
        "1.19.1-1",
        "1.19.1-1.1",
        "1.19.1-1.1ubuntu0.1~esm1"
      ]
    },
    {
      "ecosystem_specific": {
        "binaries": [
          {
            "binary_name": "simplesamlphp",
            "binary_version": "1.19.7-1+deb12u1ubuntu0.1"
          }
        ]
      },
      "package": {
        "ecosystem": "Ubuntu:24.04:LTS",
        "name": "simplesamlphp",
        "purl": "pkg:deb/ubuntu/simplesamlphp@1.19.7-1+deb12u1ubuntu0.1?arch=source\u0026distro=noble"
      },
      "ranges": [
        {
          "events": [
            {
              "introduced": "0"
            }
          ],
          "type": "ECOSYSTEM"
        }
      ],
      "versions": [
        "1.19.7-1",
        "1.19.7-1+deb12u1ubuntu0.1"
      ]
    },
    {
      "ecosystem_specific": {
        "binaries": [
          {
            "binary_name": "simplesamlphp",
            "binary_version": "1.19.7-2"
          }
        ]
      },
      "package": {
        "ecosystem": "Ubuntu:26.04:LTS",
        "name": "simplesamlphp",
        "purl": "pkg:deb/ubuntu/simplesamlphp@1.19.7-2?arch=source\u0026distro=resolute"
      },
      "ranges": [
        {
          "events": [
            {
              "introduced": "0"
            }
          ],
          "type": "ECOSYSTEM"
        }
      ],
      "versions": [
        "1.19.7-2"
      ]
    }
  ],
  "aliases": [],
  "details": "The SimpleSAMLphp SAML2 library is a PHP library for SAML2 related functionality. Prior to versions 4.19.3, 4.20.2, 5.0.6, and 6.2.1, the HTTPArtifact::receive() flow can treat an unsigned embedded SAML Response as cryptographically valid for the wrong identity provider. SOAPClient::addSSLValidator() attaches a TLS-based validator to the outer SOAP ArtifactResponse, while the embedded Response receives a validator that delegates to the outer message and is later checked against metadata selected from the embedded response issuer rather than necessarily the artifact issuer. SOAPClient::validateSSL() returns normally when the TLS public key does not match the key being validated, and SAML2\\Message::validate() treats a validator call that does not throw as successful. In a multi-IdP federation, a malicious or lower-trust IdP can therefore provide an ArtifactResponse containing an unsigned Response that claims a higher-trust victim IdP as issuer and authenticate as arbitrary users with attacker-chosen assertion attributes, NameID, and session data. This issue is fixed in versions 4.19.3, 4.20.2, 5.0.6, and 6.2.1.",
  "id": "UBUNTU-CVE-2026-49283",
  "modified": "2026-09-15T17:47:33Z",
  "published": "2026-08-19T15:17:00Z",
  "references": [
    {
      "type": "REPORT",
      "url": "https://ubuntu.com/security/CVE-2026-49283"
    },
    {
      "type": "REPORT",
      "url": "https://www.cve.org/CVERecord?id=CVE-2026-49283"
    }
  ],
  "related": [],
  "schema_version": "1.7.0",
  "severity": [
    {
      "score": "CVSS:3.1/AV:N/AC:L/PR:H/UI:N/S:C/C:H/I:H/A:N",
      "type": "CVSS_V3"
    },
    {
      "score": "medium",
      "type": "Ubuntu"
    }
  ],
  "upstream": [
    "CVE-2026-49283"
  ]
}

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.

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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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Action not permitted

CVE-2026-49283 (GCVE-0-2026-49283)

FKIE_CVE-2026-49283

GHSA-6929-8P9F-26JX

Summary

Impact

UBUNTU-CVE-2026-49283 (CVE-2026-49283)

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