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CVE-2025-40942 Siemens CVE debrief

CVE-2025-40942 affects Siemens TeleControl Server Basic and is described by CISA as a local privilege escalation vulnerability that could allow an attacker to run arbitrary code with elevated privileges. The advisory reports a CVSS v3.1 score of 8.8 (High) with a local attack vector and elevated impact. Siemens recommends updating to V3.1.2.4 or later.

Vendor
Siemens
Product
TeleControl Server Basic
CVSS
HIGH 8.8
CISA KEV
Not listed in stored evidence
Original CVE published
2026-01-13
Original CVE updated
2026-01-14
Advisory published
2026-01-13
Advisory updated
2026-01-14

Who should care

Organizations that deploy or administer Siemens TeleControl Server Basic, especially in industrial control system or OT environments, should prioritize this issue because successful exploitation could elevate a local attacker to privileged code execution.

Technical summary

The published advisory characterizes the flaw as a local privilege escalation with CVSS:3.1/AV:L/AC:L/PR:L/UI:N/S:C/C:H/I:H/A:H. That means exploitation requires local access and some privileges, but can lead to elevated code execution and broad confidentiality, integrity, and availability impact. The vendor remediation is to upgrade TeleControl Server Basic to version V3.1.2.4 or later.

Defensive priority

High. Even though exploitation is local, the combination of privilege escalation and arbitrary code execution with elevated privileges makes this a serious risk for systems where an attacker can obtain a foothold.

Recommended defensive actions

  • Upgrade Siemens TeleControl Server Basic to V3.1.2.4 or later.
  • Verify which hosts run TeleControl Server Basic and confirm their current version against the vendor advisory.
  • Restrict local access and administrative privileges on affected systems to reduce escalation opportunity.
  • Monitor affected hosts for unexpected privileged process creation or configuration changes.
  • Apply standard industrial control system hardening and defense-in-depth practices referenced by CISA.

Evidence notes

This debrief is based on the CISA CSAF advisory ICSA-26-015-03 for Siemens TeleControl Server Basic and the linked Siemens ProductCERT advisory SSA-192617. The source states the issue is a local privilege escalation that can allow arbitrary code execution with elevated privileges, assigns CVSS v3.1 8.8/High, and recommends updating to V3.1.2.4 or later. Timing context uses the advisory publication date of 2026-01-13 and the republication/update date of 2026-01-14 from the source record.

Sources and references

Verified primary and authoritative sources

  • CVE-2025-40942 CVE Program record

    Publisher, destination, and source semantics verified

    URL: https://www.cve.org/CVERecord?id=CVE-2025-40942

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

  • CVE-2025-40942 NVD vulnerability detail

    Publisher, destination, and source semantics verified

    URL: https://nvd.nist.gov/vuln/detail/CVE-2025-40942

    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-26-015-03.json

    cisa_csaf

  • Source reference

    Unverified legacy reference

    URL: https://cert-portal.siemens.com/productcert/csaf/ssa-192617.json

    Reference

  • Source reference

    Unverified legacy reference

    URL: https://cert-portal.siemens.com/productcert/html/ssa-192617.html

    Reference

  • Source reference

    Unverified legacy reference

    URL: https://www.cisa.gov/news-events/ics-advisories/icsa-26-015-03

    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.