PatchSiren cyber security CVE debrief

CVE-2024-35845 Siemens CVE debrief

This CVE addresses a missing NUL termination vulnerability in the Linux kernel's Intel wireless (iwlwifi) driver debug TLV handling. The iwl_fw_ini_debug_info_tlv structure is used as a string without guaranteed termination, which could lead to out-of-bounds read conditions. Siemens has identified this vulnerability as affecting the GNU/Linux subsystem within their SIMATIC S7-1500 TM MFP industrial control product. The vulnerability is classified as MEDIUM severity with a CVSS 3.1 score of 5.5, indicating local attack vector with low attack complexity and privileges required, resulting in high availability impact. No confidentiality or integrity impacts are associated with this vulnerability.

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 systems with enabled GNU/Linux subsystems should prioritize access controls. Industrial control system operators in manufacturing, process control, and critical infrastructure sectors using this hardware platform need to implement compensating controls. Security teams responsible for OT/ICS environments should incorporate this into their vulnerability management programs given the absence of an available patch.

Technical summary

The vulnerability exists in the iwlwifi driver's debug TLV (Type-Length-Value) parsing code. The iwl_fw_ini_debug_info_tlv structure contains string data that may not be properly NUL-terminated. When this structure is used as a C string without explicit termination guarantees, string operations may read beyond the allocated buffer boundary. This constitutes a classic missing NUL termination weakness (CWE-20: Improper Input Validation). The attack requires local access to the affected GNU/Linux subsystem with low privileges. Successful exploitation results in denial of service (high availability impact) through potential system crash or instability. No confidentiality breach or data integrity compromise is indicated by the CVSS vector.

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 future Siemens security advisories regarding patch availability
Apply defense-in-depth strategies for industrial control system environments per CISA guidance

Evidence notes

Vulnerability originates from Linux kernel iwlwifi driver (wifi: iwlwifi: dbg-tlv). Siemens product advisory ICSA-24-102-01 confirms affected product as SIMATIC S7-1500 TM MFP GNU/Linux subsystem. CVSS vector confirms local attack scope with availability impact only.

Official resources

2024-04-09