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PatchSiren cyber security CVE debrief

CVE-2025-38222 Siemens CVE debrief

CVE-2025-38222 is an integer-overflow defect in the Linux kernel ext4 inline_data write path that can lead to a kernel BUG/Oops when a write with a very large offset is processed. The supplied Siemens/CISA advisory corpus associates this CVE with SIMATIC S7-1500 CPU family products and states that no fix is currently available, so the practical response is to reduce local access to the embedded GNU/Linux subsystem and apply the listed mitigations. The supplied CVSS vector rates this as a Medium availability issue (5.5) with no confidentiality or integrity impact.

Vendor
Siemens
Product
SIMATIC S7-1500 CPU 1518-4 PN/DP MFP (6ES7518-4AX00-1AB0)
CVSS
MEDIUM 5.5
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

Siemens SIMATIC S7-1500 operators, OT/ICS asset owners, Linux subsystem administrators on affected devices, and vulnerability/patch management teams responsible for industrial control environments.

Technical summary

The CVE description says ext4_prepare_inline_data used an unsigned int length, so pos + len could truncate during ext4_generic_write_inline_data. That can let write_begin succeed with an incorrect small length, and write_end later reaches BUG_ON(pos + len > EXT4_I(inode)->i_inline_size) in ext4_write_inline_data, causing a kernel BUG/Oops. The described fix is to use loff_t for the len parameter. In the supplied advisory corpus, Siemens ties the issue to the SIMATIC S7-1500 CPU family and its additional GNU/Linux subsystem, but the corpus does not provide a fixed version.

Defensive priority

Medium, with elevated operational priority in OT environments because the advisory lists no fix and the impact is a kernel crash/availability loss.

Recommended defensive actions

  • Restrict interactive shell access on the additional GNU/Linux subsystem to trusted personnel only.
  • Only build and run applications from trusted sources.
  • Track Siemens ProductCERT and CISA advisories for a future fixed release and deploy it when available.
  • Apply CISA/Siemens defense-in-depth guidance for the affected SIMATIC S7-1500 environment.
  • Review whether local users or automation can reach the embedded Linux write path, and limit that access where possible.

Evidence notes

Source item ICSA-25-162-05 (published 2025-06-10, last updated 2026-05-14) contains the CVE description, affected Siemens SIMATIC S7-1500 product names, and mitigation text stating no fix is currently available. The CVE record links to the Linux ext4 inline_data overflow description and a CVSS 3.1 vector of AV:L/AC:L/PR:L/UI:N/S:U/C:N/I:N/A:H. The advisory corpus also includes Siemens CSAF/HTML references and CISA advisory links.

Sources and references

Verified primary and authoritative sources

  • CVE-2025-38222 CVE Program record

    Publisher, destination, and source semantics verified

    URL: https://www.cve.org/CVERecord?id=CVE-2025-38222

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

  • CVE-2025-38222 NVD vulnerability detail

    Publisher, destination, and source semantics verified

    URL: https://nvd.nist.gov/vuln/detail/CVE-2025-38222

    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.