PatchSiren

PatchSiren cyber security CVE debrief

CVE-2024-35815 Siemens CVE debrief

A vulnerability in the Linux kernel's asynchronous I/O (AIO) subsystem could allow a local attacker to cause a denial of service condition. The flaw exists in the fs/aio code where kiocb_set_cancel_fn() may receive a struct kiocb pointer that is not embedded within struct aio_kiocb. Due to compiler-dependent behavior, the req->ki_ctx read could occur before the IOCB_AIO_RW flag check, potentially leading to unsafe memory access. The vulnerability was resolved by reordering the code to ensure the IOCB_AIO_RW test always precedes the ki_ctx read. This issue affects Siemens SIMATIC S7-1500 TM MFP industrial control systems that utilize the GNU/Linux subsystem.

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 industrial control systems with the GNU/Linux subsystem enabled. System administrators responsible for OT/ICS security posture. Security teams monitoring Linux kernel vulnerabilities in embedded industrial environments.

Technical summary

The vulnerability stems from undefined compiler behavior in the Linux kernel's asynchronous I/O implementation. The function kiocb_set_cancel_fn() in fs/aio.c performs a type conversion from struct kiocb to struct aio_kiocb without first verifying that the kiocb is actually embedded within an aio_kiocb structure. The IOCB_AIO_RW flag check, which would prevent this unsafe conversion, may be reordered by the compiler to occur after the req->ki_ctx member access. This creates a window where invalid memory could be dereferenced. The fix restructures the code to enforce the correct evaluation order regardless of compiler optimization. The CVSS 3.1 vector AV:L/AC:L/PR:L/UI:N/S:U/C:N/I:N/A:H indicates local attack vector with low complexity, requiring low privileges, with high availability impact but no confidentiality or integrity impact.

Defensive priority

medium

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 per CISA guidance

Evidence notes

The vulnerability description indicates this is a compiler-dependent code ordering issue in the Linux kernel AIO subsystem. The fix ensures proper validation sequence by checking IOCB_AIO_RW before accessing ki_ctx. Siemens has confirmed this affects the GNU/Linux subsystem of SIMATIC S7-1500 TM MFP devices. No fix is currently available per vendor advisory.

Sources and references

Verified primary and authoritative sources

  • CVE-2024-35815 CVE Program record

    Publisher, destination, and source semantics verified

    URL: https://www.cve.org/CVERecord?id=CVE-2024-35815

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

  • CVE-2024-35815 NVD vulnerability detail

    Publisher, destination, and source semantics verified

    URL: https://nvd.nist.gov/vuln/detail/CVE-2024-35815

    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.