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PatchSiren cyber security CVE debrief

CVE-2024-42304 Siemens CVE debrief

A vulnerability in the Linux kernel's ext4 filesystem implementation could allow a local attacker to cause a denial of service condition. The issue stems from improper handling of directory blocks where the first directory block could be a hole, leading to potential filesystem corruption or system instability. This vulnerability was resolved by ensuring the first directory block is properly allocated and not a hole.

Vendor
Siemens
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 industrial control systems with the GNU/Linux subsystem enabled. System administrators responsible for securing OT/ICS environments and maintaining filesystem integrity on embedded Linux systems.

Technical summary

This vulnerability exists in the Linux kernel's ext4 filesystem driver. The issue occurs when the first directory block could be allocated as a hole (unallocated space), which can lead to undefined behavior, filesystem corruption, or denial of service. The resolution ensures that the first directory block is properly allocated and not a hole, maintaining filesystem integrity. The vulnerability requires local access with low privileges and has no impact on confidentiality or integrity, but can cause high availability impact through denial of service.

Defensive priority

medium

Recommended defensive actions

  • Limit access to the interactive shell of the additional GNU/Linux subsystem to trusted personnel only
  • Only build and run applications from trusted sources
  • Monitor for patches from Siemens for the SIMATIC S7-1500 TM MFP GNU/Linux subsystem
  • Apply defense-in-depth strategies for industrial control systems per CISA guidance

Evidence notes

The vulnerability description indicates this was a resolved issue in the Linux kernel's ext4 filesystem. The fix ensures proper directory block allocation to prevent holes in the first directory block.

Official resources

public