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PatchSiren cyber security CVE debrief

CVE-2024-33621 Linux CVE debrief

A vulnerability in the Linux kernel's IPvlan network driver could allow a local, privileged attacker to cause a denial of service (DoS) condition. The flaw exists in the `ipvlan_process_v4_outbound` and `ipvlan_process_v6_outbound` functions, which improperly use `skb->sk` (socket buffer socket pointer) during packet processing. This can lead to a NULL pointer dereference or use-after-free condition, resulting in a system crash. The vulnerability affects Siemens SIMATIC S7-1500 TM MFP devices that utilize the GNU/Linux subsystem. Exploitation requires local access with high privileges to the interactive shell of the GNU/Linux subsystem. No patch is currently available from the vendor.

Vendor
Linux
Product
SIMATIC S7-1500 TM MFP - GNU/Linux subsystem
CVSS
MEDIUM 4.4
CISA KEV
Not listed in stored evidence
Original CVE published
2025-08-12
Original CVE updated
2026-02-25
Advisory published
2025-08-12
Advisory updated
2026-02-25

Who should care

Organizations operating Siemens SIMATIC S7-1500 TM MFP industrial controllers with the GNU/Linux subsystem enabled. OT security teams, industrial network administrators, and asset owners in manufacturing, process control, and critical infrastructure sectors should prioritize access controls and monitoring for this unpatched vulnerability.

Technical summary

The vulnerability resides in the Linux kernel's IPvlan (IP virtual LAN) driver, specifically in the outbound packet processing functions for IPv4 and IPv6. The functions `ipvlan_process_v4_outbound` and `ipvlan_process_v6_outbound` incorrectly reference `skb->sk`, the socket pointer in the socket buffer structure. Under certain conditions, this pointer may be NULL or invalid, leading to a NULL pointer dereference or use-after-free when the driver attempts to access socket-related data during packet transmission. This results in a kernel oops or panic, causing system availability impact. The vulnerability is classified as CWE-1287 (Improper Validation of Specified Type of Input).

Defensive priority

medium

Recommended defensive actions

  • Restrict access to the interactive shell of the GNU/Linux subsystem to trusted personnel only
  • Only build and run applications from trusted sources
  • Monitor for anomalous system crashes or kernel panics on affected devices
  • Apply vendor patches when they become available
  • Review network segmentation to limit exposure of affected industrial control systems

Evidence notes

Vulnerability disclosed in Linux kernel ipvlan driver. Affects Siemens SIMATIC S7-1500 TM MFP GNU/Linux subsystem. CVSS 3.1 score 4.4 (MEDIUM). No fix currently available per vendor advisory.

Sources and references

Verified primary and authoritative sources

  • CVE-2024-33621 CVE Program record

    Publisher, destination, and source semantics verified

    URL: https://www.cve.org/CVERecord?id=CVE-2024-33621

    CVE Program - Official CVE Program record with source-provided CVE metadata.

  • CVE-2024-33621 NVD vulnerability detail

    Publisher, destination, and source semantics verified

    URL: https://nvd.nist.gov/vuln/detail/CVE-2024-33621

    NIST National Vulnerability Database - Official NIST NVD detail page and source-specific vulnerability assessment.

Supplemental references

  • Source item URL

    Unverified legacy reference

    URL: https://raw.githubusercontent.com/cisagov/CSAF/develop/csaf_files/OT/white/2024/icsa-24-102-01.json

    cisa_csaf

  • Source reference

    Unverified legacy reference

    URL: https://cert-portal.siemens.com/productcert/csaf/ssa-265688.json

    Reference

  • Source reference

    Unverified legacy reference

    URL: https://cert-portal.siemens.com/productcert/html/ssa-265688.html

    Reference

  • Source reference

    Unverified legacy reference

    URL: https://www.cisa.gov/news-events/ics-advisories/icsa-24-102-01

    Reference

  • Source reference

    Unverified legacy reference

    URL: https://www.cisa.gov/news-events/ics-alerts/ics-alert-10-301-01

    Reference

  • Source reference

    Unverified legacy reference

    URL: https://www.cisa.gov/resources-tools/resources/ics-recommended-practices

    Reference

  • Source reference

    Unverified legacy reference

    URL: https://www.cisa.gov/topics/industrial-control-systems

    Reference

  • Source reference

    Unverified legacy reference

    URL: https://www.cisa.gov/sites/default/files/recommended_practices/NCCIC_ICS-CERT_Defense_in_Depth_2016_S508C.pdf

    Reference

Methodology and review provenance

AI-assisted synthesis based on stored public vulnerability evidence. System validation, approval state, and publication status do not by themselves establish human review of this revision. PatchSiren helps prioritize defensive review and does not prove exposure or remediation on any system.