CVE-2026-49284
SimpleSAMLphp SP accepts a response from an unexpected IdP when unsigned `Response/InResponseTo` is combined with a signed assertion lacking `SubjectConfirmationData/InResponseTo`
Impact
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.
Affected packages
| Ecosystem | Package | Affected | Fixed in |
|---|---|---|---|
| composer | simplesamlphp/simplesamlphp | >= 2.5.0, <= 2.5.1 | 2.5.2 |
Affected products
| Vendor | Product | Affected versions |
|---|---|---|
| Simplesamlphp | Simplesamlphp | before 2.4.7 from 2.5.0 before 2.5.2 |
Weakness classification
References
- NVD record
- CVE.org record
- GitHub advisory
- https://github.com/advisories/GHSA-q8r6-xj3f-wrrm
- https://github.com/simplesamlphp/simplesamlphp/security/advisories/GHSA-q8r6-xj3f-wrrm
- https://github.com/simplesamlphp/simplesamlphp/releases/tag/v2.4.7
- https://github.com/simplesamlphp/simplesamlphp/releases/tag/v2.5.2