Admidio is an open-source user management solution. Prior to version 5.0.9, the SAML IdP implementation in Admidio's SSO module uses the AssertionConsumerServiceURL value directly from incoming SAML AuthnRequest messages as the destination for the SAML response, without validating it against the registered ACS URL (smc_acs_url) stored in the database for the corresponding service provider client. An attacker who knows the Entity ID of a registered SP client can craft a SAML AuthnRequest with an arbitrary AssertionConsumerServiceURL, causing the IdP to send the signed SAML response -- containing user identity attributes (login name, email, roles, profile fields) -- to an attacker-controlled URL. This issue has been patched in version 5.0.9.
History

Thu, 07 May 2026 14:15:00 +0000

Type Values Removed Values Added
Metrics ssvc

{'options': {'Automatable': 'no', 'Exploitation': 'poc', 'Technical Impact': 'partial'}, 'version': '2.0.3'}


Thu, 07 May 2026 05:45:00 +0000

Type Values Removed Values Added
First Time appeared Admidio
Admidio admidio
Vendors & Products Admidio
Admidio admidio

Thu, 07 May 2026 04:15:00 +0000

Type Values Removed Values Added
Description Admidio is an open-source user management solution. Prior to version 5.0.9, the SAML IdP implementation in Admidio's SSO module uses the AssertionConsumerServiceURL value directly from incoming SAML AuthnRequest messages as the destination for the SAML response, without validating it against the registered ACS URL (smc_acs_url) stored in the database for the corresponding service provider client. An attacker who knows the Entity ID of a registered SP client can craft a SAML AuthnRequest with an arbitrary AssertionConsumerServiceURL, causing the IdP to send the signed SAML response -- containing user identity attributes (login name, email, roles, profile fields) -- to an attacker-controlled URL. This issue has been patched in version 5.0.9.
Title Admidio: SAML Response Sent to Unvalidated Assertion Consumer Service URL from AuthnRequest
Weaknesses CWE-20
CWE-601
References
Metrics cvssV3_1

{'score': 8.2, 'vector': 'CVSS:3.1/AV:N/AC:L/PR:N/UI:R/S:C/C:H/I:L/A:N'}


cve-icon MITRE

Status: PUBLISHED

Assigner: GitHub_M

Published:

Updated: 2026-05-07T13:44:01.169Z

Reserved: 2026-04-22T03:53:24.405Z

Link: CVE-2026-41670

cve-icon Vulnrichment

Updated: 2026-05-07T13:43:49.583Z

cve-icon NVD

Status : Deferred

Published: 2026-05-07T04:16:30.993

Modified: 2026-05-07T15:16:08.560

Link: CVE-2026-41670

cve-icon Redhat

No data.

cve-icon OpenCVE Enrichment

Updated: 2026-05-07T05:45:06Z