{"dataType":"CVE_RECORD","dataVersion":"5.2","cveMetadata":{"cveId":"CVE-2026-49283","assignerOrgId":"a0819718-46f1-4df5-94e2-005712e83aaa","state":"PUBLISHED","assignerShortName":"GitHub_M","dateReserved":"2026-05-28T20:07:58.861Z","datePublished":"2026-08-19T14:47:05.519Z","dateUpdated":"2026-08-19T18:19:10.978Z"},"containers":{"cna":{"title":"SimpleSAMLphp HTTP-Artifact TLS validator confusion allows cross-IdP authentication bypass","problemTypes":[{"descriptions":[{"cweId":"CWE-295","lang":"en","description":"CWE-295: Improper Certificate Validation","type":"CWE"}]}],"metrics":[{"cvssV3_1":{"attackComplexity":"LOW","attackVector":"NETWORK","availabilityImpact":"NONE","baseScore":8.7,"baseSeverity":"HIGH","confidentialityImpact":"HIGH","integrityImpact":"HIGH","privilegesRequired":"HIGH","scope":"CHANGED","userInteraction":"NONE","vectorString":"CVSS:3.1/AV:N/AC:L/PR:H/UI:N/S:C/C:H/I:H/A:N","version":"3.1"}}],"references":[{"name":"https://github.com/simplesamlphp/saml2/security/advisories/GHSA-6929-8p9f-26jx","tags":["x_refsource_CONFIRM"],"url":"https://github.com/simplesamlphp/saml2/security/advisories/GHSA-6929-8p9f-26jx"},{"name":"https://github.com/simplesamlphp/saml2/commit/4a71b20d8d845579fd0a54d6449c265b40db459d","tags":["x_refsource_MISC"],"url":"https://github.com/simplesamlphp/saml2/commit/4a71b20d8d845579fd0a54d6449c265b40db459d"},{"name":"https://github.com/simplesamlphp/saml2/commit/a2c1ac588c70d7b7998546cf32675fb113f22a5f","tags":["x_refsource_MISC"],"url":"https://github.com/simplesamlphp/saml2/commit/a2c1ac588c70d7b7998546cf32675fb113f22a5f"},{"name":"https://github.com/simplesamlphp/saml2/commit/d5c213132ef671c0018a11252322034dbddd735a","tags":["x_refsource_MISC"],"url":"https://github.com/simplesamlphp/saml2/commit/d5c213132ef671c0018a11252322034dbddd735a"},{"name":"https://github.com/simplesamlphp/saml2/commit/e2df7992609964951b2a3e7d6566b7427b2a968f","tags":["x_refsource_MISC"],"url":"https://github.com/simplesamlphp/saml2/commit/e2df7992609964951b2a3e7d6566b7427b2a968f"}],"affected":[{"vendor":"simplesamlphp","product":"saml2","versions":[{"version":"< 4.19.3","status":"affected"},{"version":">= 4.20.0, < 4.20.2","status":"affected"},{"version":">= 5.0.0, < 5.0.6","status":"affected"},{"version":">= 6.0.0, < 6.2.1","status":"affected"}]}],"providerMetadata":{"orgId":"a0819718-46f1-4df5-94e2-005712e83aaa","shortName":"GitHub_M","dateUpdated":"2026-08-19T14:47:05.519Z"},"descriptions":[{"lang":"en","value":"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."}],"source":{"advisory":"GHSA-6929-8p9f-26jx","discovery":"UNKNOWN"}},"adp":[{"metrics":[{"other":{"type":"ssvc","content":{"timestamp":"2026-08-19T18:16:10.690773Z","id":"CVE-2026-49283","options":[{"Exploitation":"none"},{"Automatable":"no"},{"Technical Impact":"total"}],"role":"CISA Coordinator","version":"2.0.3"}}}],"title":"CISA ADP Vulnrichment","providerMetadata":{"orgId":"134c704f-9b21-4f2e-91b3-4a467353bcc0","shortName":"CISA-ADP","dateUpdated":"2026-08-19T18:19:10.978Z"}}]}}