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CVE-2024-50058 Siemens CVE debrief

CVE-2024-50058 is a NULL pointer dereference vulnerability in the Linux kernel's serial core subsystem. The issue exists in `uart_shutdown()` where a `uart_port_dtr_rts(uport, false)` call is made without verifying that `uport` is non-NULL, despite a preceding NULL check that acknowledges `uport` can be NULL. This vulnerability is triggered only when the HUPCL (hang up on close) flag is set, which limits its exposure. The flaw was identified through Coverity static analysis (CID 1585130). Siemens has confirmed this vulnerability affects the GNU/Linux subsystem of the SIMATIC S7-1500 TM MFP industrial control system. No patch is currently available from Siemens for this product. The vulnerability has a CVSS 3.1 score of 5.5 (MEDIUM) with a local attack vector, requiring low privileges and no user interaction, resulting in high availability impact.

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

Operators of Siemens SIMATIC S7-1500 TM MFP industrial control systems utilizing the GNU/Linux subsystem; security teams managing OT/ICS environments with Linux-based embedded systems; kernel maintainers and developers working with serial subsystem code

Technical summary

The vulnerability resides in `drivers/tty/serial/serial_core.c` in the Linux kernel's UART shutdown path. When `uart_shutdown()` is called with the HUPCL flag set in `c_cflag`, the code path executes `uart_port_dtr_rts(uport, false)` without validating that `uport` is non-NULL. A preceding NULL check added in commit af224ca2df29 (serial: core: Prevent unsafe uart port access, part 3) demonstrates that `uport` can legitimately be NULL in this context, yet the DTR/RTS manipulation was not moved inside the protective conditional. This results in a NULL pointer dereference when the HUPCL-controlled code path is taken with a NULL `uport`. The vulnerability is local-only, requires low privileges, and causes denial of service (system crash) through the high availability impact vector.

Defensive priority

medium

Recommended defensive actions

  • Restrict interactive shell access to the GNU/Linux subsystem on affected Siemens SIMATIC S7-1500 TM MFP devices to trusted personnel only
  • Build and execute only applications from trusted sources on affected systems
  • Monitor for kernel updates from Siemens that address this vulnerability in the SIMATIC S7-1500 TM MFP GNU/Linux subsystem
  • Apply defense-in-depth strategies for industrial control systems per CISA guidance
  • Review serial port configurations and minimize use of HUPCL where operationally feasible

Evidence notes

The vulnerability description indicates this is a defensive coding issue where a NULL pointer check was added in commit af224ca2df29 but the subsequent `uart_port_dtr_rts()` call was not protected. The Coverity CID 1585130 reference confirms static analysis identification. Siemens CSAF data confirms affected product and no fix availability.

Sources and references

Verified primary and authoritative sources

  • CVE-2024-50058 CVE Program record

    Publisher, destination, and source semantics verified

    URL: https://www.cve.org/CVERecord?id=CVE-2024-50058

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

  • CVE-2024-50058 NVD vulnerability detail

    Publisher, destination, and source semantics verified

    URL: https://nvd.nist.gov/vuln/detail/CVE-2024-50058

    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.