{
  "affected": [
    {
      "ranges": [
        {
          "database_specific": {
            "extracted_events": [
              {
                "introduced": "0"
              },
              {
                "fixed": "4.19.3"
              },
              {
                "introduced": "4.20.0"
              },
              {
                "fixed": "4.20.2"
              },
              {
                "introduced": "5.0.0"
              },
              {
                "fixed": "5.0.6"
              },
              {
                "introduced": "6.0.0"
              },
              {
                "fixed": "6.2.1"
              }
            ],
            "source": [
              "AFFECTED_FIELD",
              "REFERENCES"
            ]
          },
          "events": [
            {
              "introduced": "0"
            },
            {
              "introduced": "0da0f24bbdd751f8589da8112960eaf002b4f1f4"
            },
            {
              "introduced": "c5afe836888890b859ae7b224619c380bb87349d"
            },
            {
              "introduced": "11a1c44f248a95e688f97de6ad118d9c3a67afea"
            },
            {
              "fixed": "d5c213132ef671c0018a11252322034dbddd735a"
            },
            {
              "fixed": "8e76ef75ce44015f336a6a905e08a0d17616a0e2"
            },
            {
              "fixed": "a2c1ac588c70d7b7998546cf32675fb113f22a5f"
            },
            {
              "fixed": "f3c4d4fbe44639e63a94e023e7198e5d243d6422"
            },
            {
              "fixed": "4a71b20d8d845579fd0a54d6449c265b40db459d"
            },
            {
              "fixed": "e2df7992609964951b2a3e7d6566b7427b2a968f"
            }
          ],
          "repo": "https://github.com/simplesamlphp/saml2",
          "type": "GIT"
        }
      ]
    }
  ],
  "aliases": [
    "GHSA-6929-8p9f-26jx"
  ],
  "database_specific": {
    "cna_assigner": "GitHub_M",
    "cwe_ids": [
      "CWE-295"
    ],
    "osv_generated_from": "https://github.com/CVEProject/cvelistV5/tree/main/cves/2026/49xxx/CVE-2026-49283.json"
  },
  "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": "CVE-2026-49283",
  "modified": "2026-08-21T03:30:31.975694574Z",
  "published": "2026-08-19T14:47:05.519Z",
  "references": [
    {
      "type": "ADVISORY",
      "url": "https://github.com/CVEProject/cvelistV5/tree/main/cves/2026/49xxx/CVE-2026-49283.json"
    },
    {
      "type": "ADVISORY",
      "url": "https://github.com/simplesamlphp/saml2/security/advisories/GHSA-6929-8p9f-26jx"
    },
    {
      "type": "ADVISORY",
      "url": "https://nvd.nist.gov/vuln/detail/CVE-2026-49283"
    },
    {
      "type": "FIX",
      "url": "https://github.com/simplesamlphp/saml2/commit/4a71b20d8d845579fd0a54d6449c265b40db459d"
    },
    {
      "type": "FIX",
      "url": "https://github.com/simplesamlphp/saml2/commit/a2c1ac588c70d7b7998546cf32675fb113f22a5f"
    },
    {
      "type": "FIX",
      "url": "https://github.com/simplesamlphp/saml2/commit/d5c213132ef671c0018a11252322034dbddd735a"
    },
    {
      "type": "FIX",
      "url": "https://github.com/simplesamlphp/saml2/commit/e2df7992609964951b2a3e7d6566b7427b2a968f"
    }
  ],
  "schema_version": "1.9.0",
  "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"
}