{"id":"CVE-2026-49284","summary":"SimpleSAMLphp SP accepts a response from an unexpected IdP when unsigned `Response/InResponseTo` is combined with a signed assertion lacking `SubjectConfirmationData/InResponseTo`","details":"SimpleSAMLphp versions before 1.18.6 contain an information disclosure vulnerability. Prior to 2.4.7 and 2.5.2, SimpleSAMLphp's SAML SP ACS path does not enforce the IdP selected for an SP-initiated login when unsigned Response/InResponseTo is combined with a signed assertion lacking SubjectConfirmationData/InResponseTo, allowing a response issued by one trusted IdP to be bound to SP state created for another IdP and bypass flows that route users to a specific IdP, including deployments that set enable_unsolicited to false. This issue is fixed in versions 2.4.7 and 2.5.2.","aliases":["GHSA-q8r6-xj3f-wrrm"],"modified":"2026-08-12T03:51:19.133282010Z","published":"2026-07-17T19:17:23.897Z","database_specific":{"osv_generated_from":"https://github.com/CVEProject/cvelistV5/tree/main/cves/2026/49xxx/CVE-2026-49284.json","cna_assigner":"GitHub_M","cwe_ids":["CWE-345"]},"references":[{"type":"WEB","url":"https://github.com/simplesamlphp/simplesamlphp/releases/tag/v2.4.7"},{"type":"WEB","url":"https://github.com/simplesamlphp/simplesamlphp/releases/tag/v2.5.2"},{"type":"ADVISORY","url":"https://github.com/CVEProject/cvelistV5/tree/main/cves/2026/49xxx/CVE-2026-49284.json"},{"type":"ADVISORY","url":"https://github.com/simplesamlphp/simplesamlphp/security/advisories/GHSA-q8r6-xj3f-wrrm"},{"type":"ADVISORY","url":"https://nvd.nist.gov/vuln/detail/CVE-2026-49284"}],"affected":[{"ranges":[{"type":"GIT","repo":"https://github.com/simplesamlphp/simplesamlphp","events":[{"introduced":"0"},{"fixed":"8b871fab276d4b0b2a09a727ceaa10ca3abd5d30"},{"introduced":"a21e4f6bd67e41c6bc5ef2b69e1cd1ed42f41e28"},{"fixed":"e04c29a772769bb0bacba0ba072b599779d158c4"}],"database_specific":{"source":["CPE_RANGE","REFERENCES"],"cpe":"cpe:2.3:a:simplesamlphp:simplesamlphp:*:*:*:*:*:*:*:*","extracted_events":[{"introduced":"0"},{"fixed":"2.4.7"},{"introduced":"2.5.0"},{"fixed":"2.5.2"}]}}],"versions":["v2.4.6","v2.4.5","v2.5.0","v2.4.4","v2.4.3","v2.4.2","v2.4.1","v2.4.0","v2.3.0","v2.1.0-rc1","v2.0.4","v2.0.3","v2.0.2","v2.0.1","v2.0.0","v2.0.0-rc3","v2.0.0-rc2","v2.0.0-rc1","v2.0.0-beta.11","v2.0.0-beta.4","v2.0.0-beta.3","v2.0.0-beta.2","v2.0.0-beta.1","v1.15.0-rc1","v1.12.0"],"database_specific":{"source":"https://storage.googleapis.com/cve-osv-conversion/osv-output/CVE-2026-49284.json"}}],"schema_version":"1.9.0","severity":[{"type":"CVSS_V3","score":"CVSS:3.1/AV:N/AC:L/PR:L/UI:N/S:U/C:L/I:H/A:N"}]}