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PatchSiren cyber security CVE debrief

CVE-2023-42363 Siemens CVE debrief

CVE-2023-42363 is a use-after-free vulnerability in BusyBox's xasprintf function that Siemens and CISA map to affected Siemens SINEC OS firmware on several industrial networking products, including the RUGGEDCOM RST2428P and multiple SCALANCE families. The supplied advisory rates the issue Medium (CVSS 5.5) and indicates denial-of-service impact as the main consequence.

Vendor
Siemens
Product
RUGGEDCOM RST2428P (6GK6242-6PA00)
CVSS
MEDIUM 5.5
CISA KEV
Not listed in stored evidence
Original CVE published
2026-01-28
Original CVE updated
2026-02-25
Advisory published
2026-01-28
Advisory updated
2026-02-25

Who should care

OT/ICS operators and asset owners running Siemens devices that use SINEC OS firmware, especially the listed RUGGEDCOM and SCALANCE product families. Security teams should also care if they manage firmware baselines, remote access, or maintenance workflows that could expose local-user interaction paths.

Technical summary

The source corpus describes a BusyBox 1.36.1 use-after-free in xfuncs_printf.c:344, specifically in xasprintf. The supplied CVSS vector is AV:L/AC:L/PR:N/UI:R/S:U/C:N/I:N/A:H, which points to local access with user interaction and high availability impact, with no confidentiality or integrity impact scored. The republished Siemens/CISA advisory also clarifies that only SINEC OS firmware is impacted.

Defensive priority

Medium; prioritize promptly on any exposed or operationally critical Siemens SINEC OS deployment because the impact is availability loss on industrial networking equipment.

Recommended defensive actions

  • Update affected devices to SINEC OS V3.3 or later, per Siemens remediation guidance.
  • Confirm whether each deployed Siemens product is actually running SINEC OS firmware before scheduling remediation.
  • Inventory the listed affected models and firmware versions, including RUGGEDCOM RST2428P and the SCALANCE families named in the advisory.
  • Limit local access and operator interaction paths on affected systems until updates are applied.
  • Track the Siemens ProductCERT advisory SSA-089022 and CISA advisory ICSA-26-043-06 for product-specific guidance and any further revision history.

Evidence notes

Supported by the Siemens ProductCERT advisory SSA-089022 and CISA republished CSAF advisory ICSA-26-043-06, both referenced in the source item. The corpus explicitly states a BusyBox v1.36.1 use-after-free in xasprintf/xfuncs_printf.c:344, gives the CVSS 3.1 vector AV:L/AC:L/PR:N/UI:R/S:U/C:N/I:N/A:H, and lists a vendor fix to update to V3.3 or later. The revision history in the supplied source notes a later clarification that only SINEC OS firmware is impacted.

Sources and references

Verified primary and authoritative sources

  • CVE-2023-42363 CVE Program record

    Publisher, destination, and source semantics verified

    URL: https://www.cve.org/CVERecord?id=CVE-2023-42363

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

  • CVE-2023-42363 NVD vulnerability detail

    Publisher, destination, and source semantics verified

    URL: https://nvd.nist.gov/vuln/detail/CVE-2023-42363

    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/2026/icsa-26-043-06.json

    cisa_csaf

  • Source reference

    Unverified legacy reference

    URL: https://cert-portal.siemens.com/productcert/csaf/ssa-089022.json

    Reference

  • Source reference

    Unverified legacy reference

    URL: https://cert-portal.siemens.com/productcert/html/ssa-089022.html

    Reference

  • Source reference

    Unverified legacy reference

    URL: https://www.cisa.gov/news-events/ics-advisories/icsa-26-043-06

    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.