PatchSiren cyber security CVE debrief

CVE-2024-43858 Siemens CVE debrief

CVE-2024-43858 is a HIGH severity (CVSS 7.8) array-index-out-of-bounds vulnerability in the JFS (Journaled File System) implementation of the Linux kernel, specifically within the `diFree` function. The vulnerability was resolved in the upstream Linux kernel. Siemens has identified this vulnerability as affecting the GNU/Linux subsystem of the SIMATIC S7-1500 TM MFP industrial control system. The vulnerability requires local access with low privileges, and successful exploitation can result in complete compromise of confidentiality, integrity, and availability. No patch is currently available from Siemens; mitigation relies on restricting access to trusted personnel and ensuring only trusted applications are executed.

Vendor: Siemens
Product: SIMATIC S7-1500 TM MFP - GNU/Linux subsystem
CVSS: HIGH 7.8
CISA KEV: Not listed in stored evidence
Original CVE published: 2024-04-09
Original CVE updated: 2026-05-14
Advisory published: 2024-04-09
Advisory updated: 2026-05-14

Who should care

Organizations operating Siemens SIMATIC S7-1500 TM MFP systems with the GNU/Linux subsystem enabled, particularly in industrial automation and critical infrastructure environments. Security teams responsible for OT/ICS asset protection, Linux kernel maintainers in embedded industrial systems, and compliance officers tracking CVE remediation for industrial control systems.

Technical summary

The vulnerability exists in the `diFree` function of the JFS (Journaled File System) implementation in the Linux kernel. An array-index-out-of-bounds condition can occur, potentially leading to memory corruption. The CVSS 3.1 vector (AV:L/AC:L/PR:L/UI:N/S:U/C:H/I:H/A:H) indicates that a low-privileged local attacker can exploit this without user interaction to achieve high impact on confidentiality, integrity, and availability. The vulnerability classifies under CWE-129 (Improper Validation of Array Index). Siemens has confirmed impact to the GNU/Linux subsystem of SIMATIC S7-1500 TM MFP, an industrial automation platform. No vendor patch is currently available; mitigation depends on access controls and trusted application execution.

Defensive priority

HIGH

Recommended defensive actions

Restrict interactive shell access to the GNU/Linux subsystem to trusted personnel only
Implement application whitelisting to ensure only trusted applications are built and executed
Monitor for anomalous local process behavior indicative of memory corruption exploitation
Apply vendor patches when released by Siemens
Review and implement CISA ICS recommended practices for defense-in-depth

Evidence notes

CVE published 2024-04-09 per official CVE record. CISA ICS advisory ICSA-24-102-01 published same date. Siemens CSAF advisory SSA-265688 cross-referenced. CVSS 3.1 vector AV:L/AC:L/PR:L/UI:N/S:U/C:H/I:H/A:H confirmed from source. CWE-129 (Improper Validation of Array Index) identified. No KEV listing. No fix available per vendor remediation statement.

Official resources

2024-04-09