{"id":"UBUNTU-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":"2026-09-15T20:16:39.374603917Z","published":"2026-08-19T15:17:00Z","upstream":["CVE-2026-49283"],"references":[{"type":"REPORT","url":"https://ubuntu.com/security/CVE-2026-49283"},{"type":"REPORT","url":"https://www.cve.org/CVERecord?id=CVE-2026-49283"}],"affected":[{"package":{"name":"simplesamlphp","ecosystem":"Ubuntu:Pro:16.04:LTS","purl":"pkg:deb/ubuntu/simplesamlphp?arch=source&distro=esm-apps-legacy%2Fxenial"},"ranges":[{"type":"ECOSYSTEM","events":[{"introduced":"0"}]}],"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":"1.14.0-1ubuntu2+esm1"}]},"database_specific":{"source":"https://github.com/canonical/ubuntu-security-notices/blob/main/osv/cve/2026/UBUNTU-CVE-2026-49283.json"}},{"package":{"name":"simplesamlphp","ecosystem":"Ubuntu:Pro:18.04:LTS","purl":"pkg:deb/ubuntu/simplesamlphp?arch=source&distro=esm-apps%2Fbionic"},"ranges":[{"type":"ECOSYSTEM","events":[{"introduced":"0"}]}],"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_version":"1.15.3-1ubuntu0.1~esm1","binary_name":"simplesamlphp"}]},"database_specific":{"source":"https://github.com/canonical/ubuntu-security-notices/blob/main/osv/cve/2026/UBUNTU-CVE-2026-49283.json"}},{"package":{"name":"simplesamlphp","ecosystem":"Ubuntu:Pro:20.04:LTS","purl":"pkg:deb/ubuntu/simplesamlphp?arch=source&distro=esm-apps%2Ffocal"},"ranges":[{"type":"ECOSYSTEM","events":[{"introduced":"0"}]}],"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":"1.18.4-1ubuntu0.1~esm1"}]},"database_specific":{"source":"https://github.com/canonical/ubuntu-security-notices/blob/main/osv/cve/2026/UBUNTU-CVE-2026-49283.json"}},{"package":{"name":"simplesamlphp","ecosystem":"Ubuntu:Pro:22.04:LTS","purl":"pkg:deb/ubuntu/simplesamlphp?arch=source&distro=esm-apps%2Fjammy"},"ranges":[{"type":"ECOSYSTEM","events":[{"introduced":"0"}]}],"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":"1.19.1-1.1ubuntu0.1~esm1"}]},"database_specific":{"source":"https://github.com/canonical/ubuntu-security-notices/blob/main/osv/cve/2026/UBUNTU-CVE-2026-49283.json"}},{"package":{"name":"simplesamlphp","ecosystem":"Ubuntu:24.04:LTS","purl":"pkg:deb/ubuntu/simplesamlphp?arch=source&distro=noble"},"ranges":[{"type":"ECOSYSTEM","events":[{"introduced":"0"}]}],"versions":["1.19.7-1","1.19.7-1+deb12u1ubuntu0.1"],"ecosystem_specific":{"binaries":[{"binary_version":"1.19.7-1+deb12u1ubuntu0.1","binary_name":"simplesamlphp"}]},"database_specific":{"source":"https://github.com/canonical/ubuntu-security-notices/blob/main/osv/cve/2026/UBUNTU-CVE-2026-49283.json"}},{"package":{"name":"simplesamlphp","ecosystem":"Ubuntu:26.04:LTS","purl":"pkg:deb/ubuntu/simplesamlphp?arch=source&distro=resolute"},"ranges":[{"type":"ECOSYSTEM","events":[{"introduced":"0"}]}],"versions":["1.19.7-2"],"ecosystem_specific":{"binaries":[{"binary_version":"1.19.7-2","binary_name":"simplesamlphp"}]},"database_specific":{"source":"https://github.com/canonical/ubuntu-security-notices/blob/main/osv/cve/2026/UBUNTU-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"},{"type":"Ubuntu","score":"medium"}]}