PatchSiren cyber security CVE debrief

CVE-2024-26882 Siemens CVE debrief

CVE-2024-26882 is a medium-severity vulnerability (CVSS 5.5) in the Linux kernel's IP tunnel implementation, specifically within the `ip_tunnel_rcv()` function. The flaw involves improper handling of inner packet headers during IP tunnel reception, which can lead to denial-of-service conditions. The vulnerability was published on April 9, 2024, and affects Siemens SIMATIC S7-1500 TM MFP industrial control systems that utilize the GNU/Linux subsystem. As of the latest advisory update (September 9, 2025), no patch is available from the vendor. The vulnerability requires local access with low privileges to exploit, and successful exploitation results in high availability impact without affecting confidentiality or integrity.

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 programmable logic controllers with the GNU/Linux subsystem enabled, particularly in manufacturing, process control, and critical infrastructure environments. Security teams responsible for OT/ICS asset protection and patch management should prioritize access controls given the absence of an available fix.

Technical summary

The vulnerability exists in `ip_tunnel_rcv()` where the inner header of tunneled IP packets may not be properly pulled into the skb (socket buffer) before processing. This can result in out-of-bounds access or null pointer dereference when the kernel attempts to process the inner packet header, leading to a system crash and denial of service. The flaw is classified under CWE-20 (Improper Input Validation). Exploitation requires local access with low privileges and no user interaction, making it primarily a concern for multi-user environments or compromised accounts on affected industrial systems.

Defensive priority

medium

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 activity on affected Siemens SIMATIC S7-1500 TM MFP systems
Apply defense-in-depth strategies per ICS-CERT recommended practices pending vendor patch availability
Subscribe to Siemens ProductCERT and CISA ICS advisories for patch notification

Evidence notes

Vulnerability description and CVSS scoring derived from CISA CSAF advisory ICSA-24-102-01. Vendor attribution to Siemens confirmed through CSAF product tree. Remediation status of 'no fix available' explicitly stated in source advisory dated through September 9, 2025.

Official resources

published