PatchSiren cyber security CVE debrief

CVE-2024-2466 curl CVE debrief

A vulnerability in libcurl's mbedTLS integration causes complete TLS certificate validation bypass when connecting to hosts specified as IP addresses. The flaw affects Siemens SINEC NMS and potentially other products using vulnerable libcurl builds with mbedTLS. CISA published advisory ICSA-24-319-04 on November 12, 2024, coordinating with Siemens' security advisory SSA-331112. The vulnerability is not listed in CISA's Known Exploited Vulnerabilities catalog.

Vendor: curl
Product: SIMATIC S7-1500 CPU 1518-4 PN/DP MFP (6ES7518-4AX00-1AB0)
CVSS: HIGH 7.1
CISA KEV: Not listed in stored evidence
Original CVE published: 2023-12-12
Original CVE updated: 2025-08-12
Advisory published: 2023-12-12
Advisory updated: 2025-08-12

Who should care

Organizations operating Siemens SINEC NMS network management systems, industrial control system operators using libcurl with mbedTLS, and security teams responsible for TLS certificate validation in embedded or industrial networking products.

Technical summary

When libcurl is built with mbedTLS and configured to connect to a host specified as an IP address rather than a hostname, the library incorrectly avoids calling the set hostname function. This causes complete bypass of server certificate validation for all TLS-based protocols including HTTPS, FTPS, IMAPS, POP3S, and SMTPS. The vulnerability stems from improper hostname handling logic that treats IP addresses differently from DNS names, failing to establish the expected TLS identity verification context.

Defensive priority

HIGH

Recommended defensive actions

Update Siemens SINEC NMS to V3.0 SP1 or later version per vendor guidance
Audit systems for libcurl builds using mbedTLS that connect to IP addresses directly
Implement network segmentation for industrial control systems per CISA recommended practices
Monitor TLS connections for anomalous certificate validation behavior
Review application configurations to avoid direct IP address connections where hostname validation is required

Evidence notes

CVE published and modified 2024-11-12 per official record. CISA advisory ICSA-24-319-04 published same date. Siemens remediation guidance specifies update to V3.0 SP1 or later.

Official resources

2024-11-12