CVE-2026-41670 Admidio: SAML Response Sent to Unvalidated Assertion Consumer Service URL from AuthnRequest
Attackers can redirect SAML responses to malicious URLs, exposing user identity data and enabling account takeover in Admidio.
- Exploited in the wild
- Not known
- Login needed
- Not needed
- Attackable
- Over the internet
- Victim action needed
- A user has to click or open something
- Fix
- Available
What is CVE-2026-41670?
CVE-2026-41670 is a high-severity vulnerability in admidio, published on 7 May 2026. An attacker can exploit it over the internet without logging in, and only if a user opens a file or follows a link.
Official 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.
Which versions are affected by CVE-2026-41670?
2 open source packages ship an affected version, including admidio/admidio.
| Package | Affected | Fixed in |
|---|---|---|
admidio/admidio Packagist | All versions | 5.0.9 |
admidio/admidio Packagist | All versions | 5.0.9 |
How do I fix CVE-2026-41670?
Upgrade admidio/admidio to 5.0.9 or later.
Is CVE-2026-41670 being exploited?
It is not confirmed as exploited in the wild, but public exploit code for CVE-2026-41670 exists.
Sources
Also known as GHSA-p9w9-87c8-m235.