PatchSiren

PatchSiren cyber security CVE debrief

CVE-2024-26950 Siemens CVE debrief

A vulnerability in the Linux kernel's WireGuard netlink interface could allow a local attacker to cause a denial of service condition. The issue stems from improper device access patterns in the WireGuard netlink code path, where the device was accessed through peer structures rather than through the proper context (ctx) mechanism. This flaw was resolved by modifying the code to access the device through ctx instead of peer, ensuring proper reference handling and preventing potential null pointer dereference or use-after-free scenarios. The vulnerability affects Siemens SIMATIC S7-1500 TM MFP industrial control systems that utilize the GNU/Linux subsystem with WireGuard VPN functionality.

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, particularly those using WireGuard VPN functionality. System administrators responsible for securing industrial control environments, OT security teams, and infrastructure operators in manufacturing, process control, and critical infrastructure sectors should prioritize access controls until vendor patches become available. Security teams should also monitor for anomalous local activity on affected systems given the local attack vector requirement.

Technical summary

The vulnerability exists in the WireGuard netlink implementation within the Linux kernel. The code incorrectly accessed device structures through peer pointers rather than through the proper context (ctx) mechanism. This architectural flaw could lead to race conditions, null pointer dereferences, or use-after-free vulnerabilities when the peer structure becomes invalid while the device reference is still being used. The fix ensures proper device reference acquisition through the ctx parameter, maintaining correct object lifetime management. The vulnerability is exploitable locally with low privileges and requires no user interaction, making it a concern for multi-user industrial systems where the GNU/Linux subsystem is accessible to multiple operators or maintenance accounts.

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 vendor security updates from Siemens for the SIMATIC S7-1500 TM MFP product line
  • Apply defense-in-depth strategies for industrial control system environments per CISA guidance
  • Review and restrict local user privileges on affected GNU/Linux subsystems to reduce attack surface

Evidence notes

The vulnerability description indicates a code-level fix in the Linux kernel WireGuard implementation. The CVSS 3.1 vector (AV:L/AC:L/PR:L/UI:N/S:U/C:N/I:N/A:H) confirms local attack vector with low attack complexity, requiring low privileges but no user interaction, resulting in high availability impact. The source advisory (ICSA-24-102-01) from CISA provides official government-sourced confirmation of this vulnerability affecting industrial control systems.

Official resources

2024-04-09