# Siemens Mendix SAML module signature validation flaw

Published: 2025-08-19 · Severity: routine · Sectors: manufacturing
Canonical: https://vorant.io/reports/f509bab2-bd16-57c1-94d1-16039234b677/siemens-mendix-saml-module-signature-validation-flaw

> Improper cryptographic signature verification in Siemens Mendix SAML allows unauthenticated account hijacking in certain SSO configurations.

Siemens Mendix SAML module contains an improper cryptographic signature verification vulnerability (CVE-2025-40758, CVSS 8.7) in versions prior to V3.6.21 (Mendix 9.24), V4.0.3 (Mendix 10.12), and V4.1.2 (Mendix 10.21). The flaw stems from insufficient enforcement of signature validation and binding checks within the SAML authentication flow, allowing unauthenticated remote attackers to hijack user accounts in specific SSO configurations. Attack complexity is noted as high, and no known public exploitation has been reported to CISA at the time of advisory publication.

Affected organizations should prioritize patching to the latest compatible version and ensure the UseEncryption configuration option is enabled as an interim mitigation. The vulnerability has worldwide deployment impact, particularly affecting critical manufacturing environments. Network segmentation and access controls remain essential defensive measures for ICS environments running these modules.

## Mentioned in this report

- Vulnerabilities: CVE-2025-40758

Source reporting: https://www.cisa.gov/news-events/ics-advisories/icsa-25-231-02

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