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CVE-2025-21772 Siemens CVE debrief

CVE-2025-21772 is a HIGH severity vulnerability (CVSS 7.1) affecting the GNU/Linux subsystem of Siemens SIMATIC S7-1500 TM MFP industrial control systems. The vulnerability stems from improper handling of malformed partition tables in the mac partition driver, which could allow a local attacker with low privileges to cause denial of service or potentially read sensitive information. The issue was first published on April 9, 2024, and has been tracked through multiple advisory updates through September 2025. Siemens has not released a patch for this vulnerability; mitigation relies on restricting access to the interactive shell and ensuring only trusted applications are executed.

Vendor
Siemens
Product
SIMATIC S7-1500 TM MFP - GNU/Linux subsystem
CVSS
HIGH 7.8
CISA KEV
Not listed in stored evidence
Original CVE published
2025-02-27
Original CVE updated
2026-07-30
Advisory published
2025-02-27
Advisory updated
2026-07-30

Who should care

Industrial control system operators using Siemens SIMATIC S7-1500 TM MFP with the GNU/Linux subsystem enabled; OT security teams managing embedded Linux environments in manufacturing and critical infrastructure; compliance officers tracking unpatched vulnerabilities in operational technology environments

Technical summary

The vulnerability exists in the mac partition driver within the Linux kernel's partition handling code. When processing a malformed or 'bogus' partition table, the driver fails to properly validate input, leading to potential out-of-bounds read conditions or null pointer dereferences. This can result in kernel panic (availability impact) or information disclosure from kernel memory (confidentiality impact). The attack requires local access with low privileges and no user interaction, making it exploitable by any user with shell access to the GNU/Linux subsystem.

Defensive priority

HIGH

Recommended defensive actions

  • Restrict interactive shell access to the GNU/Linux subsystem to trusted personnel only
  • Implement application whitelisting to ensure only trusted applications are built and executed
  • Monitor for anomalous partition table access attempts in system logs
  • Apply defense-in-depth strategies per ICS-CERT recommended practices
  • Subscribe to Siemens ProductCERT and CISA ICS advisories for patch availability notifications

Evidence notes

The vulnerability description 'partitions: mac: fix handling of bogus partition table' indicates a kernel-level issue in partition table parsing. The CVSS vector (AV:L/AC:L/PR:L/UI:N/S:U/C:H/I:N/A:H) confirms local attack vector with high impact to confidentiality and availability but no integrity impact.

Sources and references

Verified primary and authoritative sources

  • CVE-2025-21772 CVE Program record

    Publisher, destination, and source semantics verified

    URL: https://www.cve.org/CVERecord?id=CVE-2025-21772

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

  • CVE-2025-21772 NVD vulnerability detail

    Publisher, destination, and source semantics verified

    URL: https://nvd.nist.gov/vuln/detail/CVE-2025-21772

    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/2024/icsa-24-102-01.json

    cisa_csaf

  • Source reference

    Unverified legacy reference

    URL: https://cert-portal.siemens.com/productcert/csaf/ssa-265688.json

    Reference

  • Source reference

    Unverified legacy reference

    URL: https://cert-portal.siemens.com/productcert/html/ssa-265688.html

    Reference

  • Source reference

    Unverified legacy reference

    URL: https://www.cisa.gov/news-events/ics-advisories/icsa-24-102-01

    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.