CVE-2026-49283

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{"affected": [{"affectedData": [{"product": "saml2", "vendor": "simplesamlphp", "versions": [{"status": "affected", "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"}]}], "source": "security-advisories@github.com"}], "cveTags": [], "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."}], "id": "CVE-2026-49283", "lastModified": "2026-09-18T20:09:01.757", "metrics": {"cvssMetricV31": [{"cvssData": {"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"}, "exploitabilityScore": 2.3, "impactScore": 5.8, "source": "security-advisories@github.com", "type": "Secondary"}], "ssvcV203": [{"source": "134c704f-9b21-4f2e-91b3-4a467353bcc0", "ssvcData": {"id": "CVE-2026-49283", "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"}]}

{}

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