PatchSiren

PatchSiren cyber security CVE debrief

CVE-2025-38198 Siemens CVE debrief

CVE-2025-38198 is a Linux kernel fbcon defect called out in Siemens/CISA advisory ICSA-25-162-05 for the SIMATIC S7-1500 CPU family. The supplied description says writing to the store_modes sysfs node can reach an unregistered console path where con2fb_map contains -1, leading to an array-index-out-of-bounds access. The described fix is to have fbcon_info_from_console() return NULL instead of indexing with -1. The advisory assigns CVSS 3.1 7.8 (HIGH) and states that no fix is currently available for the listed products.

Vendor
Siemens
Product
SIMATIC S7-1500 CPU 1518-4 PN/DP MFP (6ES7518-4AX00-1AB0)
CVSS
HIGH 7.8
CISA KEV
Not listed in stored evidence
Original CVE published
2025-06-10
Original CVE updated
2026-05-14
Advisory published
2025-06-10
Advisory updated
2026-05-14

Who should care

Operators of the listed Siemens SIMATIC S7-1500 CPU 1518/1518F and SIPLUS variants, especially teams that administer the additional GNU/Linux subsystem, interactive shell access, or sysfs-facing maintenance workflows in OT environments.

Technical summary

The vulnerability path described in the source corpus is local and memory-safety related: a write to the store_modes sysfs node can invoke fb_new_modelist()/fbcon_new_modelist(), which calls fbcon_info_from_console(). If con2fb_map[console] is -1 for an unregistered console, the function indexes fbcon_registered_fb[-1], triggering UBSAN array-index-out-of-bounds. The documented remediation is to return NULL so callers can fail safely when the console is not registered.

Defensive priority

High

Recommended defensive actions

  • Restrict interactive shell access to the additional GNU/Linux subsystem to trusted personnel only.
  • Apply CISA and Siemens defense-in-depth guidance for the affected OT environment.
  • Only build and run applications from trusted sources on the affected systems.
  • Review whether any administrative workflow exposes the store_modes/sysfs path and limit access to only necessary operators.
  • Monitor the Siemens ProductCERT and CISA advisory pages for a vendor fix or updated mitigation guidance.

Evidence notes

Primary facts come from the supplied CISA CSAF source item for ICSA-25-162-05 and the Siemens SSA-082556 references. The advisory publication date is 2025-06-10; the latest supplied advisory update is 2026-05-14. The source corpus includes a 'none_available' remediation entry stating that no fix is currently available. KEV is not listed in the supplied data. The vulnerability text itself describes the kernel code path, the -1 index condition, and the NULL-return fix.

Sources and references

Verified primary and authoritative sources

  • CVE-2025-38198 CVE Program record

    Publisher, destination, and source semantics verified

    URL: https://www.cve.org/CVERecord?id=CVE-2025-38198

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

  • CVE-2025-38198 NVD vulnerability detail

    Publisher, destination, and source semantics verified

    URL: https://nvd.nist.gov/vuln/detail/CVE-2025-38198

    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/2025/icsa-25-162-05.json

    cisa_csaf

  • Source reference

    Unverified legacy reference

    URL: https://cert-portal.siemens.com/productcert/csaf/ssa-082556.json

    Reference

  • Source reference

    Unverified legacy reference

    URL: https://cert-portal.siemens.com/productcert/html/ssa-082556.html

    Reference

  • Source reference

    Unverified legacy reference

    URL: https://www.cisa.gov/news-events/ics-advisories/icsa-25-162-05

    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.