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PatchSiren cyber security CVE debrief

CVE-2024-46865 Siemens CVE debrief

A use of uninitialized variable vulnerability exists in the Linux kernel's FOU (Foo Over UDP) implementation. The issue stems from improper initialization order where the `grc` variable may be used before being initialized. If the `fou` pointer is NULL, a `goto out` path is executed that references the uninitialized `grc` variable, potentially leading to information disclosure or denial of service conditions. This vulnerability affects Siemens SIMATIC S7-1500 TM MFP industrial control systems that utilize the GNU/Linux subsystem. The CVSS 3.1 score of 7.1 (HIGH) reflects local attack vector with low attack complexity, requiring low privileges but no user interaction, with impacts to confidentiality and availability.

Vendor
Siemens
Product
SIMATIC S7-1500 TM MFP - GNU/Linux subsystem
CVSS
CRITICAL 9.8
CISA KEV
Not listed in stored evidence
Original CVE published
2024-09-27
Original CVE updated
2026-08-04
Advisory published
2024-09-27
Advisory updated
2026-08-04

Who should care

Organizations operating Siemens SIMATIC S7-1500 TM MFP systems with the GNU/Linux subsystem enabled, industrial control system operators, OT security teams, and Linux kernel maintainers for embedded/industrial distributions

Technical summary

The vulnerability exists in the Linux kernel's FOU (Foo Over UDP) implementation where the `grc` variable is not initialized before potential error handling paths. When `fou` is NULL, the code executes `goto out` which references `grc` in an uninitialized state. This represents a CWE-908 (Use of Uninitialized Resource) weakness. The affected code path requires local access with low privileges, making this primarily a concern for multi-user systems or compromised application scenarios. The confidentiality and availability impacts stem from potential information leakage or system instability from use of undefined memory values.

Defensive priority

HIGH

Recommended defensive actions

  • Restrict interactive shell access to the GNU/Linux subsystem to trusted personnel only
  • Only build and run applications from trusted sources
  • Monitor for vendor security updates from Siemens for patch availability
  • Apply defense-in-depth strategies for industrial control system environments
  • Review and implement CISA ICS recommended practices for securing control systems

Evidence notes

The vulnerability description indicates this is a kernel-level initialization bug in the FOU (Foo Over UDP) networking subsystem. The fix involves ensuring `grc` is initialized before any potential error paths that could reference it. Siemens has confirmed this affects the GNU/Linux subsystem of their SIMATIC S7-1500 TM MFP product line.

Sources and references

Verified primary and authoritative sources

  • CVE-2024-46865 CVE Program record

    Publisher, destination, and source semantics verified

    URL: https://www.cve.org/CVERecord?id=CVE-2024-46865

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

  • CVE-2024-46865 NVD vulnerability detail

    Publisher, destination, and source semantics verified

    URL: https://nvd.nist.gov/vuln/detail/CVE-2024-46865

    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.