PatchSiren cyber security CVE debrief

CVE-2023-49069 Siemens CVE debrief

CVE-2023-49069 is a medium-severity (CVSS 5.3) authentication vulnerability in Siemens Mendix Runtime affecting versions V8, V9, V10, V10.6, and V10.12. The flaw involves an observable response discrepancy during username validation that allows unauthenticated remote attackers to enumerate valid usernames through differential responses. Published on September 10, 2024, this vulnerability was disclosed through coordinated CISA and Siemens advisories. The vendor has released complete fixes across all affected version lines as of January 2025, with final mitigations for REST/web services and oData APIs added in August 2025. Organizations should prioritize updating to patched versions and migrating away from basic authentication to alternative methods such as OIDC SSO, Mendix SSO, SAML, or custom authentication.

Vendor: Siemens
Product: Mendix Runtime V8
CVSS: MEDIUM 5.3
CISA KEV: Not listed in stored evidence
Original CVE published: 2024-09-10
Original CVE updated: 2025-08-12
Advisory published: 2024-09-10
Advisory updated: 2025-08-12

Who should care

Organizations operating Siemens Mendix Runtime applications with user authentication, particularly those currently using basic authentication. Security teams responsible for identity and access management in low-code application platforms. OT/ICS security practitioners monitoring CISA advisories for industrial software components.

Technical summary

The vulnerability exists in the authentication mechanism of affected Mendix Runtime applications where username validation produces observable response discrepancies. When an attacker submits authentication requests, differential responses between valid and invalid usernames allow systematic enumeration of user accounts. This information disclosure weakness enables reconnaissance for subsequent targeted attacks. The root cause is improper handling of authentication responses that leak existence information. Complete vendor fixes were released across all affected version lines between November 2024 and January 2025, with additional mitigations for API authentication published August 12, 2025.

Defensive priority

medium

Recommended defensive actions

Update Mendix Runtime V8 to version 8.18.33 or later
Update Mendix Runtime V9 to version 9.24.31 or later
Update Mendix Runtime V10 to version 10.17.0 or later
Update Mendix Runtime V10.6 to version 10.6.19 or later
Update Mendix Runtime V10.12 to version 10.12.11 or later
For app user authentication, replace basic authentication with OIDC SSO, Mendix SSO, SAML version 4.0.0 or higher, or a custom Identity Provider
For published REST and web services and oData APIs, replace basic authentication with Custom or Active Session authentication methods
Review authentication logs for anomalous username validation patterns that may indicate enumeration attempts

Evidence notes

Vulnerability confirmed through CISA CSAF advisory with Siemens as canonical vendor source. Multiple revision cycles tracked complete fix availability across Mendix Runtime version lines from September 2024 through August 2025.

Official resources

Coordinated disclosure through CISA ICS advisory (ICSA-24-256-05) and Siemens ProductCERT