PatchSiren cyber security CVE debrief

CVE-2024-34027 Linux CVE debrief

A vulnerability in the F2FS (Flash-Friendly File System) compression implementation affects the GNU/Linux subsystem of Siemens SIMATIC S7-1500 TM MFP industrial control devices. The flaw involves filesystem metadata corruption—including block addresses in dnodes, inode fields, and the total_valid_block_count field—following a Sudden Power Off (SPO) event. This can lead to filesystem integrity issues and potential denial of service conditions on affected systems. The vulnerability is rated MEDIUM severity with a CVSS 3.1 score of 5.5, reflecting local attack vector requirements and high availability impact. No patch is currently available from the vendor.

Vendor: Linux
Product: SIMATIC S7-1500 TM MFP - GNU/Linux subsystem
CVSS: MEDIUM 5.5
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 programmable logic controllers with the GNU/Linux subsystem enabled, particularly in environments with unreliable power infrastructure or where unexpected shutdowns may occur.

Technical summary

The vulnerability exists in the F2FS compression code path where filesystem metadata structures—including block addresses stored in dnodes, inode fields, and the total_valid_block_count counter—may become corrupted following a sudden power loss event. This corruption occurs because the compression layer's metadata updates are not properly hardened against incomplete write sequences during power failure scenarios. The attack requires local access with low privileges and no user interaction, but results in high availability impact due to potential filesystem damage. The CVSS vector AV:L/AC:L/PR:L/UI:N/S:U/C:N/I:N/A:H indicates confidentiality and integrity are not directly affected, but availability is severely impacted.

Defensive priority

medium

Recommended defensive actions

Restrict interactive shell access to the GNU/Linux subsystem to trusted personnel only
Build and run applications exclusively from trusted sources
Monitor for abnormal filesystem behavior or corruption indicators following unexpected power events
Implement uninterruptible power supply (UPS) protection to reduce SPO exposure
Apply vendor patches when Siemens releases a fix for this vulnerability

Evidence notes

CVE published 2024-04-09 per CISA CSAF advisory ICSA-24-102-01. Advisory subsequently updated multiple times through 2025-09-09 with additional CVEs, but no fix has been released for this specific vulnerability. Siemens advisory SSA-265688 cross-referenced.

Official resources

2024-04-09