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PatchSiren cyber security CVE debrief

CVE-2025-31257 Siemens CVE debrief

CVE-2025-31257 is a medium-severity advisory record in the supplied corpus that points to Siemens SIMATIC CN 4100 versions earlier than V5.0. The vendor remediation is to update to V5.0 or later. The source text says the issue was addressed with improved memory handling and that processing maliciously crafted web content may lead to an unexpected crash. The supplied metadata also contains a product/description mismatch, so defenders should verify the advisory details against the linked Siemens and CISA sources before taking action.

Vendor
Siemens
Product
SIMATIC CN 4100
CVSS
MEDIUM 4.7
CISA KEV
Not listed in stored evidence
Original CVE published
2026-05-12
Original CVE updated
2026-05-14
Advisory published
2026-05-12
Advisory updated
2026-05-14

Who should care

Operators, administrators, and asset owners responsible for Siemens SIMATIC CN 4100 deployments, especially environments running versions earlier than V5.0. Security teams supporting industrial systems should also review the advisory and confirm whether any affected devices are present.

Technical summary

The supplied advisory metadata identifies an issue in Siemens SIMATIC CN 4100 vers:intdot/<5.0 and lists a fix in V5.0 or later. The description states the issue was addressed with improved memory handling and that malformed web content may trigger an unexpected crash. Based on the provided CVSS vector (AV:N/AC:L/PR:N/UI:R/S:C/C:N/I:N/A:L), the impact is limited to availability, with user interaction required. The record should be treated cautiously because the description text and product metadata are not fully aligned.

Defensive priority

Medium priority. The CVSS score is 4.7 and the impact is described as availability-only, but the affected product is an industrial system, so verified exposure should be patched during the next maintenance window.

Recommended defensive actions

  • Confirm whether Siemens SIMATIC CN 4100 is deployed and identify versions earlier than V5.0.
  • Review the Siemens advisory and CISA republication linked in the record to verify affected configurations.
  • Apply the vendor fix by upgrading to V5.0 or later.
  • Schedule the update during a controlled maintenance window and validate system behavior after upgrade.
  • Monitor affected assets for unexpected crashes or instability until remediation is complete.

Evidence notes

The source item is CISA CSAF ICSA-26-134-10, published 2026-05-12 and republished by CISA on 2026-05-14 from Siemens ProductCERT advisory SSA-032379. The remediation section in the supplied metadata states: 'Update to V5.0 or later version.' The advisory metadata lists CVSS v3.1 vector AV:N/AC:L/PR:N/UI:R/S:C/C:N/I:N/A:L and a score of 4.7. The record also includes a description mentioning improved memory handling and an unexpected crash, but the product metadata identifies Siemens SIMATIC CN 4100, so the exact affected component should be verified against the official advisory links.

Sources and references

Verified primary and authoritative sources

  • CVE-2025-31257 CVE Program record

    Publisher, destination, and source semantics verified

    URL: https://www.cve.org/CVERecord?id=CVE-2025-31257

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

  • CVE-2025-31257 NVD vulnerability detail

    Publisher, destination, and source semantics verified

    URL: https://nvd.nist.gov/vuln/detail/CVE-2025-31257

    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-26-134-10.json

    cisa_csaf

  • Source reference

    Unverified legacy reference

    URL: https://cert-portal.siemens.com/productcert/csaf/ssa-032379.json

    Reference

  • Source reference

    Unverified legacy reference

    URL: https://cert-portal.siemens.com/productcert/html/ssa-032379.html

    Reference

  • Source reference

    Unverified legacy reference

    URL: https://www.cisa.gov/news-events/ics-advisories/icsa-26-134-10

    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.