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.

No CVSS v4.0

Attack Vector Network

Attack Complexity Low

Privileges Required Low

Scope Unchanged

Confidentiality Impact Low

Integrity Impact High

Availability Impact None

User Interaction None

No CVSS v3.0

No CVSS v2

This CVE is not in the KEV list.

The EPSS score is 0.00229.

Key SSVC decision points have not yet been added.

Default status is the baseline for the product, each version can override it (e.g. patched versions marked unaffected).

Vendor Product Default status Versions
simplesamlphp simplesamlphp affected
Version Status Constraints
< 2.4.7 affected —
>= 2.5.0-rc1, < 2.5.2 affected —

No data.

No data.

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Advisories
Source ID Title
Github GHSA Github GHSA GHSA-q8r6-xj3f-wrrm SimpleSAMLphp SP accepts a response from an unexpected IdP when unsigned `Response/InResponseTo` is combined with a signed assertion lacking `SubjectConfirmationData/InResponseTo`
Fixes

Solution

No solution given by the vendor.

Workaround

No workaround given by the vendor.

References
Link Providers
https://github.com/simplesamlphp/simplesamlphp/releases/tag/v2.4.7 cve-icon
https://github.com/simplesamlphp/simplesamlphp/releases/tag/v2.5.2 cve-icon
https://github.com/simplesamlphp/simplesamlphp/security/advisories/GHSA-q8r6-xj3f-wrrm cve-icon
History

Fri, 17 Jul 2026 20:45:00 +0000

Type Values Removed Values Added
First Time appeared Simplesamlphp
Simplesamlphp simplesamlphp
Vendors & Products Simplesamlphp
Simplesamlphp simplesamlphp

Fri, 17 Jul 2026 19:30:00 +0000

Type Values Removed Values Added
Description 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.
Title SimpleSAMLphp SP accepts a response from an unexpected IdP when unsigned `Response/InResponseTo` is combined with a signed assertion lacking `SubjectConfirmationData/InResponseTo`
Weaknesses CWE-345
References
Metrics cvssV3_1

{'score': 7.1, 'vector': 'CVSS:3.1/AV:N/AC:L/PR:L/UI:N/S:U/C:L/I:H/A:N'}

Projects

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cve-icon MITRE

Status: PUBLISHED

Assigner: GitHub_M

Published:

Updated: 2026-07-17T19:17:23.897Z

Reserved: 2026-05-28T20:07:58.861Z

Link: CVE-2026-49284

cve-icon Vulnrichment

No data.

cve-icon NVD

No data.

cve-icon Redhat

No data.

cve-icon OpenCVE Enrichment

Updated: 2026-07-17T20:30:03Z

Weaknesses