Executive Threat Summary: Enterprise Identity Hijacking in Low-Code Cloud Portals

Siemens and the Cybersecurity and Infrastructure Security Agency (CISA) have issued a high-priority security advisory regarding a critical vulnerability affecting the Siemens Mendix SAML module. Detailed under CISA advisory identifier ICSA-26-258-06 and cataloged as CVE-2026-80465, the vulnerability allows unauthenticated remote threat actors to execute complete account takeovers across enterprise web applications integrated with SAML 2.0 Single Sign-On (SSO) identity providers.

Mendix is a leading enterprise low-code development platform owned by Siemens, powering mission-critical internal portals, manufacturing execution systems (MES), supply chain management consoles, and financial customer portals worldwide. The affected SAML module provides standardized federation with corporate Identity Providers (IdPs) including Microsoft Entra ID (Azure AD), Okta, Ping Identity, and Shibboleth.

Under specific identity mapping configurations, the vulnerability enables an attacker to forge or manipulate assertion attributes, coercing the service provider into issuing an authenticated session for arbitrary target users, including system administrators.

Vulnerability Mechanics: Assertion Attribute Mapping Breakdown

The flaw is classified under CWE-287 (Improper Authentication). During the processing of incoming SAML assertions sent via HTTP-POST bindings, the Mendix SAML token consumer failed to enforce strict schema-level attribute uniqueness and canonicalization:

  • Identity Spoofing via Ambiguous NameID: In configurations where user provisioning relies on flexible assertion attributes rather than strictly bound Subject NameIDs, the consumer misattributed unverified assertion attributes to existing privileged user records.
  • Session State Confusion: By submitting crafted SAML responses with unexpected attribute namespaces, an external actor can force the authentication framework to associate the incoming token with pre-existing administrative accounts without presenting valid identity credentials.

Affected Software Versions

Platform Compatibility Vulnerable Module Releases Remediated Release
Mendix 10 & Mendix 11 All releases prior to v4.2.3 v4.2.3
Mendix 9.24 LTS All releases prior to v3.6.27 v3.6.27

Remediation Playbook for Mendix Application Operators

1. Update Marketplace Module in Mendix Studio Pro

Application developers must import the patched SAML module from the Mendix Marketplace:

  1. Open the project within Mendix Studio Pro.
  2. Navigate to Marketplace and search for the official SAML module.
  3. Update the module to version 4.2.3 (for Mendix 10/11) or 3.6.27 (for Mendix 9.24).
  4. Rebuild the deployment package (.mda) and redeploy to cloud environments (Mendix Cloud, AWS, Azure, or Private Cloud).

2. Restrict IdP Entity ID Trust Mappings

Audit all configured IdP endpoints in the Mendix SAML administration console. Ensure that strict signature verification is mandated for both SAML responses and assertions, and reject assertions that lack signed Subject confirmations.