Siemens Mendix SAML Module: 1 CVE, Medium 6.8

Summary

CISA reports 1 vulnerability in Siemens Mendix SAML (Mendix 10 compatible), Mendix SAML (Mendix 11 compatible), Mendix SAML (Mendix 9 compatible). Weakness type: Authentication Bypass by Capture-replay. Mendix SAML module contains an authentication bypass vulnerability that could allow an unauthenticated remote attacker to gain unauthorized access by replaying a valid SAML assertion in IdP-initiated authentication flows. Highest CVSS v3 score: 6.8 (Medium), exploitable over the network.

At a glance

Vendor

Siemens

Products

Mendix SAML (Mendix 10 compatible), Mendix SAML (Mendix 11 compatible), Mendix SAML (Mendix 9 compatible)

CVEs

CVE-2026-89209

Highest CVSS v3

6.8 CVSS:3.1/AV:N/AC:H/PR:N/UI:R/S:U/C:H/I:H/A:N

Highest CVSS v4

–

Known exploited (KEV)

No CVE from this advisory is on the KEV list as of the last refresh

Sectors (per CISA)

Critical Manufacturing, Information Technology

Deployed

Worldwide

Vendor HQ

Germany

Vulnerabilities

Affected products (3)

• Mendix SAML (Mendix 10 compatible) < V4.2.4
• Mendix SAML (Mendix 11 compatible) < V4.2.4
• Mendix SAML (Mendix 9 compatible) < V3.6.29

Vendor fixes and mitigations (from advisory)

• Mitigation: Disable IdP-initiated SSO
• Vendor Fix: Update to V3.6.29 or later version link
• Vendor Fix: Update to V4.2.4 or later version link

Also apply CISA's standard ICS practices: minimize network exposure, keep control networks behind firewalls and isolated from business networks, and use up-to-date secure remote access.

Sources

• CISA advisory ICSA-26-302-01
• Machine-readable CSAF record
• https://cert-portal.siemens.com/productcert/csaf/ssa-137528.json
• https://cert-portal.siemens.com/productcert/html/ssa-137528.html

This page is generated automatically from the CISA advisory text. It is not a substitute for the vendor's guidance; verify affected versions and fixes at the source before making changes to control systems.