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CVE-2024-39502 Siemens CVE debrief

CVE-2024-39502 is a use-after-free vulnerability in the Linux kernel's ionic network driver, specifically affecting the NAPI (New API) polling mechanism. The flaw occurs when `ionic_qcq_enable()` incorrectly enables NAPI for queues that were previously unregistered via `netif_napi_del()`, because the `.poll` pointer is not reset to NULL upon deletion. This can lead to calling `napi_enable()` on an unregistered queue, potentially causing system instability or denial of service conditions. The vulnerability has a CVSS score of 5.5 (MEDIUM) and was published on August 12, 2025. Siemens has identified this vulnerability as affecting certain industrial networking products running SINEC OS, including the RUGGEDCOM RST2428P and SCALANCE X-family switches. CISA and Siemens have coordinated on this advisory, with the most recent update on February 25, 2026, reflecting republication based on Siemens ProductCERT guidance. No known exploitation in the wild has been reported, and this vulnerability is not listed in CISA's Known Exploited Vulnerabilities catalog.

Vendor
Siemens
Product
RUGGEDCOM RST2428P (6GK6242-6PA00)
CVSS
MEDIUM 5.5
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 industrial networking equipment including RUGGEDCOM RST2428P and SCALANCE X-family switches in critical infrastructure environments. System administrators responsible for Linux-based industrial control systems using ionic-compatible network hardware. Security teams monitoring OT/ICS environments for kernel-level vulnerabilities that could impact network availability.

Technical summary

The ionic network driver in the Linux kernel contains a use-after-free condition in its queue configuration management. When network queues are started, `netif_napi_add()` and `napi_enable()` are called for active queues. The `ionic_qcq_enable()` function uses the `.poll` pointer to determine which queues should have NAPI enabled, expecting NULL for unused queues. However, when `netif_napi_del()` unregisters a queue's NAPI, it does not reset the `.poll` pointer to NULL. Consequently, `ionic_qcq_enable()` cannot distinguish between never-registered queues and previously-registered-then-deleted queues, leading to `napi_enable()` being called on unregistered NAPI structures. This improper state management can result in memory corruption or system crashes.

Defensive priority

medium

Recommended defensive actions

  • Apply vendor-provided firmware updates for affected Siemens SCALANCE and RUGGEDCOM products when available
  • Monitor Siemens ProductCERT security advisories for patch availability
  • Implement network segmentation for industrial control systems to limit exposure
  • Follow CISA ICS recommended practices for defense-in-depth strategies
  • Review and update incident response procedures for industrial network infrastructure

Evidence notes

Vulnerability description derived from CISA CSAF advisory ICSA-25-226-07 and Siemens ProductCERT SSA-355557. The technical root cause involves improper state tracking in the ionic driver's NAPI lifecycle management. Affected products confirmed through Siemens CSAF product tree with high confidence. Timeline reflects CISA republication on 2026-02-25 based on Siemens advisory updates.

Sources and references

Verified primary and authoritative sources

  • CVE-2024-39502 CVE Program record

    Publisher, destination, and source semantics verified

    URL: https://www.cve.org/CVERecord?id=CVE-2024-39502

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

  • CVE-2024-39502 NVD vulnerability detail

    Publisher, destination, and source semantics verified

    URL: https://nvd.nist.gov/vuln/detail/CVE-2024-39502

    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/2025/icsa-25-226-07.json

    cisa_csaf

  • Source reference

    Unverified legacy reference

    URL: https://cert-portal.siemens.com/productcert/csaf/ssa-355557.json

    Reference

  • Source reference

    Unverified legacy reference

    URL: https://cert-portal.siemens.com/productcert/html/ssa-355557.html

    Reference

  • Source reference

    Unverified legacy reference

    URL: https://www.cisa.gov/news-events/ics-advisories/icsa-25-226-07

    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.