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CVE-2024-42265 Siemens CVE debrief

CVE-2024-42265 is a speculative execution vulnerability in the Linux kernel's file descriptor handling. The issue exists in the `do_dup2()` function where branch misprediction could cause an out-of-bounds array access during speculative execution. While callers verify that `fd` does not exceed `->max_fds`, CPU speculative execution on a mispredicted path could execute `tofree = fdt->fd[fd]` with an invalid index before the branch condition is resolved. The fix applies `array_index_nospec()` to sanitize the index against speculative attacks, consistent with mitigations previously applied to `close_fd()` and `file_close_fd_locked()`. This vulnerability affects Siemens SIMATIC S7-1500 TM MFP industrial control systems running the GNU/Linux subsystem. The CVSS 3.1 score of 5.5 (MEDIUM) reflects local attack vector, low attack complexity, and low privileges required, with high availability impact. No patch is currently available from the vendor; mitigations focus on restricting access to trusted personnel and ensuring only trusted applications are executed.

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

Industrial control system operators, OT security teams, Siemens SIMATIC S7-1500 TM MFP administrators, Linux kernel maintainers for embedded/ICS environments, and organizations with defense-in-depth requirements for critical infrastructure

Technical summary

The vulnerability resides in the Linux kernel's `do_dup2()` function in `fs/file.c`. The function performs `tofree = fdt->fd[fd]` after callers verify `fd <= max_fds`, but CPU branch prediction failures can cause speculative execution of the array access with an out-of-bounds `fd` value. This creates a Spectre-class speculative execution side channel. The remediation applies `array_index_nospec(fd, fdt->max_fds)` to force the speculated index to be within bounds, matching the pattern used in `close_fd()` and `file_close_fd_locked()` mitigations. The vulnerability is exploitable only under local access conditions with low privileges, with primary impact to system availability through potential kernel instability or information disclosure via side channels.

Defensive priority

medium

Recommended defensive actions

  • Restrict interactive shell access to the GNU/Linux subsystem to trusted personnel only
  • Ensure only applications from trusted sources are built and executed on affected systems
  • Monitor for vendor security updates from Siemens CERT portal for future patch availability
  • Apply defense-in-depth strategies for industrial control systems per CISA guidance
  • Review and implement ICS-CERT recommended practices for securing industrial control environments

Evidence notes

The vulnerability description is sourced from CISA CSAF advisory ICSA-24-102-01, which references the Linux kernel fix for speculative execution in do_dup2(). The Siemens product attribution and remediation status are derived from the CSAF product tree and remediation sections. CVSS vector AV:L/AC:L/PR:L/UI:N/S:U/C:N/I:N/A:H is provided in source references.

Sources and references

Verified primary and authoritative sources

  • CVE-2024-42265 CVE Program record

    Publisher, destination, and source semantics verified

    URL: https://www.cve.org/CVERecord?id=CVE-2024-42265

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

  • CVE-2024-42265 NVD vulnerability detail

    Publisher, destination, and source semantics verified

    URL: https://nvd.nist.gov/vuln/detail/CVE-2024-42265

    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.