{"id":"DEBIAN-CVE-2026-49283","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.","modified":"2026-09-19T22:47:40.522432924Z","published":"2026-08-19T15:17:07.027Z","upstream":["CVE-2026-49283"],"references":[{"type":"ADVISORY","url":"https://security-tracker.debian.org/tracker/CVE-2026-49283"}],"affected":[{"package":{"name":"simplesamlphp","ecosystem":"Debian:12","purl":"pkg:deb/debian/simplesamlphp?arch=source&distro=bookworm"},"ranges":[{"type":"ECOSYSTEM","events":[{"introduced":"0"}]}],"versions":["1.19.7-1","1.19.7-1+deb12u1","1.19.7-1+deb12u2","1.19.7-2","2.1.8-0.1","2.2.6-1","2.3.11-1","2.3.11-2","2.4.8-1","2.5.3.1-1"],"ecosystem_specific":{"urgency":"not yet assigned"},"database_specific":{"source":"https://storage.googleapis.com/debian-osv/debian-cve-osv/DEBIAN-CVE-2026-49283.json"}},{"package":{"name":"simplesamlphp","ecosystem":"Debian:14","purl":"pkg:deb/debian/simplesamlphp?arch=source&distro=forky"},"ranges":[{"type":"ECOSYSTEM","events":[{"introduced":"0"}]}],"versions":["1.10.0-1","1.11.0-1","1.12.0-1","1.12.0~rc1-1","1.12.0~rc2-1","1.13.0-1","1.13.1-1","1.13.1-2","1.13.2-1","1.14.0-1","1.14.1-1","1.14.10-1","1.14.11-1","1.14.15-1","1.14.2-1","1.14.2-2","1.14.3-1","1.14.4-1","1.14.5-1","1.14.6-1","1.14.7-1","1.14.8-1","1.14.9-1","1.15.0-1","1.15.1-1","1.15.2-1","1.15.3-1","1.15.4-1","1.16.0-1","1.16.1-1","1.16.2-1","1.16.3-1","1.17.0-1","1.17.1-1","1.17.2-1","1.17.2-2","1.17.3-1","1.17.4-1","1.17.5-1","1.17.6-1","1.17.6-2","1.18.1-1","1.18.4-1","1.18.5-1","1.18.6-1","1.18.7-1","1.18.8-1","1.19.0-1","1.19.1-1","1.19.1-1.1","1.19.6-1","1.19.7-1","1.19.7-2","1.6.0-1","1.6.1-1","1.6.2-1","1.6.3-1","1.6.3-2","1.6.3-3","1.7.0-1","1.7.0-2","1.8.0-1","1.8.1-1","1.8.2-1","1.9.0-1","1.9.0~rc1-1","1.9.0~rc2-1","1.9.1-1","1.9.2-1","2.1.8-0.1","2.2.6-1","2.3.11-1","2.3.11-2","2.4.8-1","2.5.3.1-1"],"ecosystem_specific":{"urgency":"not yet assigned"},"database_specific":{"source":"https://storage.googleapis.com/debian-osv/debian-cve-osv/DEBIAN-CVE-2026-49283.json"}}],"schema_version":"1.9.0","severity":[{"type":"CVSS_V3","score":"CVSS:3.1/AV:N/AC:L/PR:H/UI:N/S:C/C:H/I:H/A:N"}]}